[cmars232]

I think I got here from programming.reddit, saw some interesting links, and added the RSS feed to GReader.

The connection from a community I already know is more important than the self-advertised topic of interest for a news aggregator site. I trust reddit and my homies on del.icio.us more than some site that claims to be all about some general topic of interest like startups. If such a site has something worthwhile, someone on reddit or del.icio.us will probably link it anyway.

I suppose for others, they could have a similar feeling about slashdot, or digg, or something else. At some point, I think users just get comfortable with a reasonable amount of signal to noise on a site and stick to it.