I've set up a system called Edu_RSS which is a very primitive first pass at this, and the idea here, Edu_RSS is an aggregator, there should be many instances of Edu_RSS, in the ideal world everybody would have something like this on their desktop, and it pulls in the link metadata, but it also pulls in rating metadata, and it doesn't pull it in from the entire world, the way Technorati does or the way Blogdex does, it pulls it in from my community, my network of friends. And if you set up the network in this way you can actually stop worrying about searching, because the network itself becomes the search where you go through layers of linking and so what comes out the other end is stuff that will be of interest to you. And if you're finely grained enough at the output end then you can get a very precise set of inputs. But the thing is, this set of inputs comes from the entire blogosphere of four million people rather than the randomly chosen top one hundred.
The community is the network. There is no centralized place that constitutes community, there are only people, and resources, that are distributed, that are all acting on their own behalf and in their own interests - if you ever read Marvin Minsky's "The Society of Mind", it's like that - where the network consists of a set of self-selected relations using a variety of contextual information, that I've defined as third party metadata, to establish meaning, and where this meaning not only defines the community but emerges from the community.