I got an invitation to join Linkedin from a person I know. I don't wish to join because I already have too much of an Internet presence. The page said that I may know two other people who are on Linkedin and it did name two people I know. I doubt that they know each other, however. One conclusion is that this Site has hacked my e-mail address list or that of the other three people. I welcome other ideas as to how this is happening.