Andrew Chen

Not enough by far :P I started a UK equivalent of Digg for numerous reasons. If you build it and people come then there's always a need!

In the future if they die out, so what, let the best ones win.

Nope. There aren't too many.

It's not uncommon to have multiple sites serving a single space, and eventually, users gravitate toward the ones with the best experience. Nobody has it 100% nailed, and we should encourage startups to continue to innovate, rather than mocking them. I look forward to more, and can think of many that FriendFeedFeed misses. :-)

LinkRiver, BlogCatalog and AssetBar come to mind.