“What’s Happening” to
“What’s Happening Here”
by Raffi Krikorian

What am I going to talk
about?
• What is a “place”?
• How do users expect to use “where” information?
• Where do you actually get “location” from?
• What is Twitter doing?

Location =
Context + Relevancy

Location =
Context + Relevancy
• Transforming the “What’s happening” to “What’s
happening here”
• 140 character limit
• Metadata!
• People want to talk about places

No location!

What is a “place”?

What is a “place”?
• 36o5’19.176”N, 115o10’36.084”
• A pair of decimals
• Gets a bit complicated when trying to account for
“precision”
• Doesn’t mean much to people

What is a place?
• 36o5’19.176”N,
115o10’36.084”
• Needs a map to
make sense!

A place is a polygon

A place is a name

A place is a name
• 2010 Fort Mason Center, San Francisco, CA

A place is a name
• 2010 Fort Mason Center, San Francisco, CA
• Laguna St and Marina Blvd

A place is a name
• 2010 Fort Mason Center, San Francisco, CA
• Laguna St and Marina Blvd
• “The Marina”

A place is a name
• 2010 Fort Mason Center, San Francisco, CA
• Laguna St and Marina Blvd
• “The Marina”
• Fort Mason

A place is a name
• 2010 Fort Mason Center, San Francisco, CA
• Laguna St and Marina Blvd
• “The Marina”
• Fort Mason
• WOEID and twID (28b412827a461f1e)

APIs

Original attempts
• Adding it to a Tweet
• Use myloc.me, et. al. to add text to the tweet
• Localizes mobile phone and puts location “in band”
• Takes from 140 characters
• Setting profile level locations
• Setting the user/location of a Twitter user
• There’s an API for that!
• Not a per-tweet basis

Profile location
curl -u USERNAME:PASSWORD
-d location="San Francisco, California"
http://twitter.com/account/update_location.xml

Geotagging API
• Adding it to a Tweet
• Per-tweet basis
• Out of band
• Native Twitter support
• Simple way to update status with location data
• Ability to remove geotags from tweets en masse
• Across all Twitter APIs

Geo-hose
curl "http://stream.twitter.com/1/statuses/
filter.xml?
locations=-74.5129,40.2759,-73.5019,41.2759

Trends API
• Global trends
• Currently on front page of Twitter.com
• Analysis of “hot conversations”
• Location specific trends
• Through a variety of means into trends
• Locations exposed over the API as WOEIDs
• Can ask for available trends sorted by distance from
your location

Geo-place API
• Reverse geocoder to get a list of places that a Tweet
can be attached to
• Place can then be permanently attached to the Tweet
and appears in all APIs
• Allows for “location obfuscation” rends

Annotations are the Future
• Arbitrary metadata attached to Tweets
• Can store more than one location
• Can store more than one ID

What do users expect?

Sharing coordinates
• “Geotagging”
• Photo sharing
• Talking about a
specific place
• Needs a map
• Privacy
implications

Sharing polygons
• Privacy
implications are
better
• If you thought
sharing one pair
of numbers was
bad

Sharing names
• Can make a connection to users
• Inverse relationship between privacy and granularity
• I18n hell

Working with users

Implicit vs Explicit
• Do you automatically add location content,
or does the user have to explicitly do
something?
• Because this is a privacy sensitive issue -
users want to “be in control”

Workflow
• Plan for asynchronicity
• Client may get “streamed” updated
information stream to act on
• Almost certainly need human
intervention

Lying is a feature
• Not just falsification
• Understand if you’re building a “verifiied” location
service
• Sometimes just want to annotate a comment with a
place

Privacy
• Give the user control
• Communicate to the user what’s
happening both in the client and
the server
• Can somebody else tag your house?

?????
Questions?