Facebook degrees

I'm not quite sure of the whole facebook/ bebo/ myspace worlds. People keep telling me that Hole in my Pocket and the Small World Experiment should have pages - but no one has yet explained to me what the actual benefits of such things would be. I was having a gander on facebook earlier looking up an old cinema I used to work in and I came across this page.

http://www.new.facebook.com/group.php?gid=8900080125

It appears that writer Steve Jackson decided to have a wee explore of the small world ideas as research for his book The Watcher and the results can be seen here.

http://www.steve-jackson.net/six_degrees/index.html