I’ve been to Kongregate, but not for the SNS. They are a very good flash games site. They were the first site to have Desktop Tower Defence, one of the best flash games. I’ve got no interest in talking to people I don’t know on a site based around flash games. I just assumed the SNS side was something that was happening on all sites like this and I’ve just taken no interest in it as I’ve no interest in the idea.
most sites that host flash games dont purchase the rights to games, at best they might pay for a time-limited sponsorship (if the game is particularly good) but otherwise they’ll just pay a small licence fee to host the game and then share ad revenue (from pre-roll ads embedded in the game)
Recent survey from MochiMedia might be of interest