Social Networking

There are a number of social networking sites out there. This week I received three invitations for tagged, two for linkedln and one for zorpia.com

I got the invitations from people whom I have lost touch with. I am not really sure how signing up on all these sites is exactly going to benefit me. If these people had my email address, I am certain they would have simply sent me a mail asking about my whereabouts. Instead of asking me to sign up on a site to stay in touch with them.