I'd say there're two kinds of startups which are unknown to mainstream America. One is the kinds the general public have actually used, but just may not realize

I'd say there're two kinds of startups which are unknown to mainstream America. One is the kinds the general public have actually used, but just may not realize that is a service provided by a startup company. This includes the likes of Slide or Meebo, which many more people have put their widgets on their blogs/Myspace than going on to their proprietary website. These startups are fine; they may just need more PR to the mainstream media. The startups that are really hard to reach mainstreams are those me-too startups, which are those "social network for XX" or "youtube cross wikipedia" kind of thing that users could not tell a slight difference from the sites that they have been using.