i) A Ning or Blogger for message boards: Lefora is a step in the right direction (See screenshot below). If this get enough traction and open ups its platform, lots of interesting things can happen.
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ii) Techmeme for forums: We need a way to enable forum users to track the hottest discussions in forums. There can be many different versions of Techmeme, each tracking different themes. If each of these can be streamlined to form FriendFeeds or Twitter like services, it will add a lot of value in terms of attention allocation. An alternative version of this videato become a De.cli.ous of forums where users can tag their discussions through a simple plug-in.
iii) Enabling threadless-like participation: This is granddaddy of all the opportunities. If each forum can, through the use of light weight coordination mechanisms, be coordinated in a threadless-like manner for different consumer goods, the value this unlocks is going to be awesome.