Meganiche?

It's funny reading about these meganiche sites like YTMND.com when you have already heard about them. It makes me think, "Wait... not everyone knows about 'You're the man now, dog?'" But I guess the article hits it right on when the author talks about how most of these types of sites are spread by word of mouth. I heard about it a couple years ago when my friend sent me a link online, but I never really realized thats basically the only way for others to hear about it.

The article reminded me of the Web 2.0 reading that we did, and I think that almost all of the sites discussed in that article would count is meganiche... Digg.com, ebaumsworld, Youtube. I was wondering though, when does a site move on from meganiche to something else... like Google? Or does it just become a Super-Meganiche?