The Memento protocol aims to facilitate access to past versions of web resources by integrating current and historical web content through a uniform version access capability. It addresses the limitations of web architecture that typically disregards earlier resource versions, creating a system that allows users to navigate through different states of web resources over time. Overall, Memento leverages existing systems and employs a distributed approach, ensuring scalability and robust access to archived web content.

1. The Memento Protocol and
Research Issues With Web Archiving
Michael L. Nelson
Old Dominion University
Web Science & Digital Libraries Research Group
www.cs.odu.edu/~mln/
@phonedude_mln
With:
Los Alamos National Laboratory: Herbert Van de Sompel
ODU: Michele C. Weigle, Hany SalahEldeen, Matthias Prellwitz, Justin
Brunelle, Mat Kelly, Ahmed AlSum, Scott Ainsworth
University of Virginia Colloquium
2016-09-12

3. http://web.archive.org/web/*/http://www.library.virginia.edu/
also: http://whatdiditlooklike.mementoweb.org/tagged/library.virginia.edu

6. Memento wants to make it easy
to access the Web of the Past.
6

7. Memento achieves this by technically integrating
the present Web and the past Web, by introducing
a uniform version access capability for the Web.
7

8. Content Management Systems:
• Designed to be aware of all
versions of a resource;
• Self-contained;
• Variety of proprietary version
mechanisms;
• Versions interlinked using
proprietary mechanisms.
8

9. World Wide Web:
• Designed to forget about prior
versions of a resource;
• Distributed.
9

10. There are resource versions on
the Web:
• Content Management
Systems;
• Web Archives;
• Transactional archives;
• Search engine caches.
10

11. But the Web architecture has no
way to deal with them:
• Cannot talk about a resource
as it used to exist;
• Cannot access a prior version
knowing the current one;
• Cannot access the current
version knowing a prior one;
Current approaches are ad hoc
and localized.
11

12. Memento:
• Looks at the Web as a
Content Management
System;
• Introduces the uniform
capability to access versions
on the Web;
• Does not build new archives
but leverages all systems that
host versions: Web archives,
Content Management
Systems, Software Version
Systems, etc.
12

13. Memento’s version access
approach:
• Is distributed: versions may
exist on several servers;
• Uses datetime as a global
version indicator;
• Is based on the primitives of
the Web: resource, resource
state, representation, content
negotiation, link.
13

14. Since Memento’s access approach is distributed,
and is based on Web primitives, it scales like the Web.
14

15. Memento’s core components:
• Ability to speak about a
resource as it existed in the
past;
• A bridge between present
and past: link and content
negotiation;
• A bridge between past and
present: link.
15

16. original resource and versions
16

17. bridge from present to past
17

18. bridge from past to present
18

19. Memento Framework
19

20. original resource gone
20

21. original resource’s server gone
21

22. original resource provides no link
22

23. Integrating Multiple Archives
more info: http://mementoweb.org/
https://tools.ietf.org/html/rfc7089

24. Memento wants to make it easy
to access the Web of the Past…

26. http://bit.ly/memento-for-chrome

29. http://timetravel.mementoweb.org/list/20060912144251/http://www.library.virginia.edu/
www.library.virginia.edu
in 4 different web archives

30. Long Tail of Archives
Archive.is

31. Using Only Top-k Archives
for URI Lookup Yields Good Results
Even when there are 100s of archives, we only need to talk to a few.
see: http://www.cs.odu.edu/~mln/pubs/tpdl-2013/paper_134.pdf

32. OK, so
More Archives == More Better
But why care about archiving at all?

33. Why Care About The Past?
From an anonymous WWW 2010 reviewer about our
Memento paper (emphasis mine):
"Is there any statistics to show that many or a good number of Web
users would like to get obsolete data or resources? "
one answer: replay of contemporary pages >> summary pages
http://www.slideshare.net/phonedude/why-careaboutthepast
http://www.nytimes.com/2013/06/19/books/seven-american-deaths-and-disasters-transcribes-the-news.html

34. A Youtube video of a TV show where celebrities
read “mean” Tweets about themselves
Our social discourse is dominated by the web. Q.E.D.
https://www.youtube.com/watch?v=LABGimhsEys

35. Our scholarly record is in jeopardy…
http://dx.doi.org/10.1371/journal.pone.0115253
See also: http://blog.dshr.org/2015/02/the-evanescent-web.html

36. As is our legal record…
http://www.nytimes.com/2013/09/24/us/politics/in-supreme-court-opinions-clicks-that-lead-nowhere.html
See also: http://blogs.law.harvard.edu/futureoftheinternet/2013/09/22/perma/
http://ssnat.com/

37. And our popular culture as well…
http://f-measure.blogspot.com/2009/02/pink-floyd-hour-with-pink-floyd-kqed-lp.html

38. Half-Life of Popular Music Youtube Videos
Half life
0 3 6 9 12 15 18
0.5
1.0
Month
LinearRegression
Top 40 US Singles Charts
Music Blogs @ blogspot.com
The 500 Greatest Songs
0 1 2 3 4 5 6 7 8 9 10
0.86
0.88
0.90
0.92
0.94
0.96
0.98
1.00
Weeks
MedianAbsoluteDeviation
Datasets
Top 40 US Singles Charts
Music Blogs @ blogspot.com
The 500 Greatest Songs
Matthias Prellwitz, Michael L. Nelson,
Music Video Redundancy and Half-Life in YouTube,
Proceedings of TPDL 2011
http://www.cs.odu.edu/~mln/pubs/tpdl-2011/tpdl-2011-prellwitz.pdf
Individual URLs die, but new versions arise

39. So we won’t lose every copy of “Shake It Off”…
What about the grist of history?

40. http://www.bbc.com/future/story/20120927-the-decaying-web
On January 28 2011, three days into the fierce protests that would
eventually oust the Egyptian president Hosni Mubarak, a Twitter
user called Farrah posted a link to a picture that supposedly showed
an armed man as he ran on a “rooftop during clashes between police
and protesters in Suez”. I say supposedly, because both the tweet
and the picture it linked to no longer exist. Instead they have
been replaced with error messages that claim the message – and its
contents – “doesn’t exist”.

41. Missing Tweet & Pic
https://twitter.com/Farrah3m/status/31727870736859137 http://twitpic.com/3uvo6z
http://ws-dl.blogspot.com/2013/05/2013-05-07-who-is-archiving-your-tweets.html

42. In May 2013, both are “archived” by topsy.com

43. In February 2015, they’re completely missing.
http://topsy.com/http://twitpic.com/3uvo6z

44. In 2016, redirecting…
http://topsy.com/http://twitpic.com/3uvo6z

45. …to a random (?) apple.com page
http://topsy.com/http://twitpic.com/3uvo6z

46. No Server == No HTTP Event == Nothing to Archive
http://topsy.com/http://twitpic.com/3uvo6z

47. Hany M. SalahEldeen, Michael L. Nelson, Losing My Revolution: How Many Resources Shared on Social Media Have Been
Lost?, Proceedings of TPDL 2012. http://arxiv.org/abs/1209.3026
Hany SalahEldeen, Michael L. Nelson, Resurrecting My Revolution: Using Social Link Neighborhood in Bringing Context to the
Disappearing Web, Proceedings of TPDL 2013. http://arxiv.org/abs/1309.2648
Missing: 11% year 1, 7%/year afterwards
Archived: 7% year 1, 15%/year afterwards

48. Why we need multiple,
independent archives…

49. A single archive is vulnerable
http://www.bbc.com/news/uk-politics-24924185
http://ws-dl.blogspot.com/2013/11/2013-11-21-conservative-party-speeches.html

50. Houston, Tranquility Base Here. The Eagle has landed.
see also: http://ws-dl.blogspot.com/2013/03/2013-03-22-ntrs-web-archives-and-why-we.html
http://ws-dl.blogspot.com/2013/06/2013-06-18-ntrs-memento-and-handles.html

51. http://www.theguardian.com/technology/2015/feb/19/google-acknowledges-some-people-want-right-to-be-forgotten

52. $ curl –I "http://www.thedailybeast.com/articles/2016/08/11/i-
got-three-grindr-dates-in-an-hour-in-the-olympic-village.html"
HTTP/1.1 301 Moved Permanently
Access-Control-Allow-Origin: *
Age: 0
Cache-Control: max-age=60
Content-Type: text/html; charset=iso-8859-1
Date: Thu, 18 Aug 2016 01:13:46 GMT
Location: http://www.thedailybeast.com/articles/2016/08/11/a-
note-from-the-editors.html
RealAge: 0
Server: Apache
Vary: Accept-Encoding, User-Agent
Via: 1.1 varnish
X-BackEnd: default
X-Cache: MISS
X-Cacheable: YES
X-Restarts: 0
X-UA-Device: pc
X-Varnish: 995407903
Connection: keep-alive
http://www.usnews.com/news/articles/2016-08-17/wayback-machine-wont-censor-archive-for-taste-director-says-after-olympics-article-scrubbed

53. But who pays for those extra archives?
1TB endowment = ~$4700: http://blog.dshr.org/2011/02/paying-for-long-term-storage.html
see also: http://blog.dshr.org/2011/01/memento-marketplace-for-archiving.html

54. Archives aren’t magic web sites
They’re just web sites.
If you used Mummify, you’re now left with a bunch of defunct, shortened links like:
https://mummify.it/XbmcMfE3

55. Don’t Throw Away the Original URL –
Use Robust Links!
<a href="http://www.w3.org/"
data-versionurl="https://archive.today/r7cov"
data-versiondate="2015-01-21">
my robust link to the live web</a>
<a href="https://archive.today/r7cov"
data-originalurl="http://www.w3.org/"
data-versiondate="2015-01-21">
my robust link to an archived version</a>
<!DOCTYPE html>
<html lang="en" itemscope itemtype="http://schema.org/WebPage"
itemid="http://robustlinks.mementoweb.org/spec/">
<head>
<meta charset="utf-8" />
<meta itemprop="dateModified" content="2015-02-02">
<meta itemprop="datePublished" content="2015-01-23">
<title>Page Level Metadata Is The Least You Can Do</title>
More examples / scenarios at: http://robustlinks.mementoweb.org/spec/

56. Economics Working Against Archives
“In the paper world in order to monetize their content the
copyright owner had to maximize the number of copies
of it. In the Web world, in order to monetize their content
the copyright owner has to minimize the number of copies.
Thus the fundamental economic motivation for Web
content militates against its preservation in the ways
that Herbert and I would like.”
--David Rosenthal
http://blog.dshr.org/2015/02/the-evanescent-web.html

57. “We’ll use the cloud!”

58. https://www.chriswatterston.com/blog/my-there-no-cloud-sticker
"...when all costs are taken in to account,
cloud storage is not cheaper for long-term preservation than doing it yourself
once you get to a reasonable scale.”
http://blog.dshr.org/2014/11/talk-costs-why-do-we-care.html

59. Historicity of Web Archives

60. Malaysia Airlines Flight 17 (MH17)
http://web.archive.org/web/20140717152222/http://vk.com/strelkov_info
http://www.csmonitor.com/World/Europe/2014/0717/Web-evidence-points-to-pro-Russia-rebels-in-downing-of-MH17-video
http://www.newyorker.com/magazine/2015/01/26/cobweb

62. (not really archived as well as you think)

63. Ed and I Discuss Who Has What…
https://twitter.com/phonedude_mln/status/490171976389238784

64. Remember MH17?
https://twitter.com/phonedude_mln/status/490171976389238784

65. Alex is now 404.
Would multiple archives have convinced him?
https://twitter.com/quicknquiet

66. Do we really have
“a perfect tool to produce `evidence’ of any kind”?

67. @gary4205 mansplains to @AstroKatie
https://twitter.com/AstroKatie/status/765344020184739840
see also: http://www.someecards.com/news/so-that-happened/mansplain-astronaught-jessica-meir-twitter/

68. But can you prove he didn’t say this?

69. Or that she didn’t say this?
(remember: black hats can use tools created by white hats)

70. Assessing the Quality of Web Archiving
"Hooray! It's in the archive!"
vs.
"How well was it archived?"
current:
the question
we should
be asking:

71. Temporal Drift
August 27, 2005
11:16 a.m. EDT
link

72. Temporal Drift: Now 3 Hours in the Past
August 27, 2005
11:16 a.m. EDT
link
August 27, 2005
8:00 a.m. EDT
link

73. Temporal Drift: Now 17 Days in the Future
August 27, 2005
11:16 a.m. EDT
link
August 27, 2005
8:00 a.m. EDT
link
September 13, 2005
8:12 a.m. EDT
link

74. Temporal Drift: Now 23 (or 6) Days in the Future
August 27, 2005
11:16 a.m. EDT
link
August 27, 2005
8:00 a.m. EDT
link
September 13, 2005
8:12 a.m. EDT
link
September 19, 2005
8:25 a.m. EDT
link
10+ clicks in the archive results in median drift of ~45 days (standard UI)
or ~15 days with Memento. ~2% of the sessions have drift of > 1 year.
see: http://www.cs.odu.edu/~mln/pubs/jcdl-2013/jcdl93-ainsworth.pdf

75. Sometimes the Live Web
"Leaks" Into the Archive…

76. see: http://ws-dl.blogspot.com/2012/10/2012-10-10-zombies-in-archives.html
Sept 3, 2008
2012

77. Not All Mementos Are Created Equal:
Measuring The Impact Of Missing Resources
JCDL 2014
http://www.cs.odu.edu/~mln/pubs/jcdl-2014/jcdl-2014-brunelle-damage.pdf

78. M = 0.17
D = 0.09
(live web)
M = 0.24
D = 0.41
(missing main)
M = 0.29
D = 0.36
(missing logo + navigation)
Synthetic Damage:
Removing Images From xkcd.com
damage (D) differs from % missing (M)!

79. Was missing
resource
important?
<img>and
<embed>
can leave hints
about size and
centrality.
For CSS, we
look at the
distribution of
background
color in page
divided into
vertical thirds.

80. Weights from Turker Assessment of Damage
first: establish that Turkers
can determine damaged vs.
undamaged pages (81% of the time)
second: find weights that match
Turker's rankings of (real) differently
damaged versions of the same page

81. Good News:
Although %Missing (M) is steady/increasing,
weighted Damage (D) is decreasing

82. A Framework for Evaluation of
Composite Memento Temporal Coherence
Hypertext 2015
http://ws-dl.blogspot.com/2015/12/2015-12-08-evaluating-temporal.html

83. As Presented by IA
http://web.archive.org/web/20041209190926/http://www.wunderground.org/cgi-bin/findWeather/getForecast?query=50593 (now 404, but that's a different story…)

84. Not Everything Is 200412091900926
+ 9 months

85. 1 in 20 pages complete; 1 in 5 have violations
Description
Closest
Single
Archive
Closest
Multi-
Archive
Bracket
Single
Archive
Bracket
Multi-
Archive
Completeness
Mean complete 76.1% 80.2% 76.2% 80.3%
Mean missing 23.9% 19.8% 23.8% 19.7%
Temporal Coherence
Mean prima facie coherent 41.0% 40.9% 54.7% 54.6%
Mean possibly coherent 27.3% 27.3% 12.8% 14.2%
Mean probably violative 2.5% 5.3% 2.5% 5.3%
Mean prima facie violative 5.3% 5.3% 6.2% 6.2%
At least 5% of pages can be shown to be temporal violations
http://ws-dl.blogspot.com/2015/12/2015-12-08-evaluating-temporal.html

86. Closing Observations

87. Wrong Metaphor for Web Archives

88. Web Archives Are Not Destinations
This is a destination. This is not a destination.
Memento is about linking the past and present web

89. Possible Metaphor for Viewing Past & Present?

90. Turn Archiving Into A Social Activity…
see also: http://xkcd.com/1034/,
Marshall & Shipman, JCDL 2011

91. …But Don't Use the "A" Word
Ed: Are there any zombies out there?
Shaun: Don't say that!
Ed: What?
Shaun: That.
Ed: What?
Shaun: That. The Z word. Don't say it.
Ed: Why not?
Shaun: Because it's ridiculous!
— Shaun of the Dead

92. Pinterest: Anonymous Mementos
http://media-cache-ec3.pinterest.com/upload/47639708527755289_AhxhItiQ_c.jpg
is a memento of:
http://3.bp.blogspot.com/_d0vByWRfhvU/S_Ygk_oX4xI/AAAAAAAACCQ/LXgC3S0KYEo/s400/_MG_8091.jpg
but there is no machine-readable indication of this relationship
repins are by-reference

93. When all else fails, justify project with:
“web archiving is Big Data”

94. Backup Slides

95. Archiving your internal stuff:
Transactional Archiving
https://mementoweb.github.io/SiteStory/
Never miss an update;
archive your site as it is
being viewed by users.

96. Archiving your internal stuff:
Heritrix & Wayback
Crawling your intranet: http://www.dlib.org/dlib/january16/brunelle/01brunelle.html
Crawling JS “stuff” will take 5X more storage: http://arxiv.org/abs/1601.05142
mementos of Mitre Intranet “MiiTube” – Complete With Javascript leakage

97. JavaScript == the new deep web;
use ResourceSync to make sure your URIs are exposed
<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9"
xmlns:rs="http://www.openarchives.org/rs/terms/">
<rs:ln rel="up"
href="http://example.com/dataset1/capabilitylist.xml"/>
<rs:md capability="resourcelist"
at="2013-01-03T09:00:00Z"
completed="2013-01-03T09:01:00Z"/>
<url>
<loc>http://example.com/res1</loc>
<lastmod>2013-01-02T13:00:00Z</lastmod>
<rs:md hash="md5:1584abdf8ebdc9802ac0c6a7402c03b6"
length="8876"
type="text/html"/>
</url>
<url>
<loc>http://example.com/res2</loc>
<lastmod>2013-01-02T14:00:00Z</lastmod>
<rs:md hash="md5:1e0d5cb8ef6ba40c99b14c0237be735e
sha-256:854f61290e2e197a11bc91063afce22e43f8ccc655237050ace766adc68dc784"
length="14599"
type="application/pdf"/>
</url>
</urlset>
(AKA “Fancy SiteMaps”)
http://www.openarchives.org/rs/

98. timetravel.mementoweb.org
http://timetravel.mementoweb.org/list/20140525002314/http://www.bbc.co.uk/
e.g., bbc.co.uk in six different archives…

99. Seagal’s Law
A man with a watch knows what time it is.
A man with two watches is never sure.
How to resolve conflicting archives?
Personalization, GeoIP, mobile vs. desktop, etc.
means “the” page rarely exists, only “a” page.
Mat Kelly, Justin F. Brunelle, Michele C. Weigle, and Michael L. Nelson,
A Method for Identifying Personalized Representations in Web Archives,
D-Lib Magazine, 19(11/12), 2013.
http://www.dlib.org/dlib/november13/kelly/11kelly.html

100. Thoughtful analysis: http://blog.dshr.org/2015/02/vint-cerfs-talk-at-aaas.html
Snarky analysis: http://ws-dl.blogspot.com/2015/02/2015-02-17-reactions-to-vint-cerfs.html

101. Why Care About The Past?
From an anonymous WWW 2010 reviewer about our
Memento paper (emphasis mine):
"Is there any statistics to show that many or a good number of Web
users would like to get obsolete data or resources? "
one answer: replay of contemporary pages >> summary pages
http://www.slideshare.net/phonedude/why-careaboutthepast
http://www.nytimes.com/2013/06/19/books/seven-american-deaths-and-disasters-transcribes-the-news.html

103. vs.

116. Archiving Moves At Hurricane Speed,
Most News Stories Move Faster

120. Most of the Story,
at Least as Conveyed by cnn.com,
is Missing…
in this case, you can reconstruct the events with
http://en.wikipedia.org/wiki/Virginia_Tech_massacre_timeline

121. How Much of The Web Is Archived?

122. Public Archives, ca. Late 2010 / Early 2011
Three categories of archives
• Internet Archive
• Search engine
• Other archives
UK US
See also: http://arxiv.org/abs/1212.6177

123. 1000 URIs Ordered by First Observation Date
See also: http://ws-dl.blogspot.com/2011/06/2011-06-23-how-much-of-web-is-archived.html

124. see also: http://ws-dl.blogspot.com/2013/04/2013-04-19-carbon-dating-web.html

125. How Much of the Web is Archived?
It Depends on Which Web…
Including
SE cache
Excluding
SE Cache
90% 79%
97% 68%
35% 16%
88% 19%
Changes since 2011: no more free SE APIs;
greatly reduced IA quarantine period; 15 public web archives
2013
95%
92%
23%
26%

126. Quis Archiviet Ipsos Archives?
(thanks to webmaster@archive.is for this example)

127. % curl -I http://lenta.ru/articles/2013/04/02/mat/
HTTP/1.1 302 Found
Server: nginx
Date: Tue, 03 Sep 2013 00:15:14 GMT
Content-Type: text/html; charset=utf-8
Connection: keep-alive
Status: 302 Found
Location: http://lenta.ru/f_words/
X-UA-Compatible: IE=Edge,chrome=1
Cache-Control: no-cache
X-Request-Id: bd7caae039d6312c0542cb4ad62f3847
X-Runtime: 0.005474
X-Rack-Cache: miss
current page for: http://lenta.ru/articles/2013/04/02/mat/

128. archive.org version of: http://lenta.ru/articles/2013/04/02/mat/

129. peep.us archived version of archive.org version

130. archive.is archived version of peeep.us version of archive.org version