I've heard the same things about Digg, Stumbleupon, Reddit and so on (news.YC?). What I don't get: how do you get a significant number of "friends" on those networks who are willing to watch/read your spam?

My real life friends typically don't use social networks and, not being entrepreneuers themselves, they often did not get the point when I asked them to get a stumbleupon account just to rate my site. On the other hand, I could not yet muster the motivation to worm my account onto some other people's friends list just to make them rate my submissions.

How do you handle that problem? Perhaps a "entrepreneur helps entrepreneur" network for those things would be in order?