A short description of the topology of the web.

1. A sneak peek into the web
Another way to see Internet
Guillaume Lebourgeois - December 2008

2. Your vision
A browser
Websites
An interface : search
engines

3. Reality
Websites interconnected
Topology of the web
Web is a huge graph

4. Hyperlinks
A Graph is made of nodes linked together
A link can have an orientation

5. Hyperlinks
A link from website A to website B
A
B
A reciprocal link
A
B

6. Determining website quality
Two ways :
- Text mining, semantic approach
- Topologic approach
It is better to mix both.

7. Topologic approach
Authorities : websites linked by others
A
Hubs : websites dealing a lot of links
H

8. Topologic approach
The authority is judged by the others as a
reference website.
The hub has a good knowledge of his
territory.

9. Topologic approach
These two notions must be understood
relatively to a specific territory :
A community

10. Communities
Topology : a community is a subpart of the
web with a good link density.
Semantic : a community is a subpart of the
web which shares a thematic, ideas, ...

11. Communities C2
weak link
C1
w
ea
k
lin
k C3
Let’s Observe weak links

12. Communities
Weak links : they link distant communities
together. These links are rare and stategic.
They can be considered as bridges.
Six degrees : thanks to them, there are in the
worst case 6 degrees of separation between
2 random websites.
Social : the situation is exactly the same in
the social graph.

13. Exploring
To explore these structures we can use a web
Crawler.
- Extracts links and informations
- Stores data and visits links found

14. Exploring
Begin Links
data
Crawl
Depth 1
Storage
Links
data
Crawl
Depth 2
Links
...

15. Using data
Once you’ve collected data you can :
- produce a map of the territory you explored.
- create a search engine
- imagine loads of different applications...

16. End of the presentation
Feel free to ask any question