Llinking two recent posts seen elsewhere
Namechk.com ( Check Username Availability at Multiple Social Networking Sites) bookmarked on delicious.com by Philippe " one possible use of the Facebook profile information: generating a good dictionary from fabebook-names-original.txt to brute-force password" seen on Twitter.com/adulau Now use Namechk to find all combinations of >= 2 letters used on more than 1 service. I guess there is a high probability that two identical username strings on two different services belong to the same physical person. Look at their profile/activities/pages/whatever on the various websites, you have now a wonderfull network of knowledge about these people. I also guess that if a flaw is discovered in one of these services that allows to recover users passwords, you could use the same password on all the other services for the same username. ...