Have you made real friends through XING, LinkedIn or Facebook?

Hello. I started using the XING networking site about two years ago. I let the number of contacts I had made peak at about 135 and stopped there to get to know these people better. I have watched as other people have increased their contacts to 400, 500 or well over a thousand contacts, which I find over the top! I have added LinkedIn, Livejournal and Facebook to the other sites I have contacts on, but here I have maintained a much lower profile. I would like to know if people have made real friends through these sites? or Are people only massaging their egos, by increasing the number of contacts? Also what happens, when you try to meet the people? - I find that fascinating! Looking forward to sharing experiences on this one:-)
UMart