Information gathering on targets is key for attackers. They need to understand their targets to construct more successful attacks.
Recently, I came across http://namechk.com/ I was blown away with the amount of information this site reveals.
The site promotes itself as a way to "check to see if your desired username or vanity url is still available at dozens of popular Social Networking and Social Bookmarking websites."
From an attackers standpoint, lets say I want to identify all of the resources that Jeremiah Grossman, the CTO of WhiteHat Security uses. I simply type in his blogspot id, "jeremiahgrossman" and I identify that in addition to blogspot he also posts to delicious and youtube. This is great!
For an attacker, this resource provides a way to identify additional paths of research.
