One of the problems I have with the giant popularity contest that all the Web 2.0 gizmos revolve around is that it's become normative. That is, a whole bunch of uppity Web 2.0 apps are now taking the audacious tack of telling you that you're wrong when your interests don't happen to match what's in their feed/scrape/stream/web/tag list/FOAF db/whatever. For example, Spotback, a "personal tag tracker" which promises to present you with relevant news only. The sign-up process invites you nominate up to four things you're interested in while it goes and configures feeds in the background.
In my case, it gratuitously commented that three of my chocies were "hmm, not popular" and the fourth was a complete mismatch. Cheeky, I thought, but not unexpected given that they are fairly specialist tastes which don't group tightly around any one particular source. On instructing it to proceed with setting up my customised tracker, it then asked me if I wanted fix up the "errors" or "ignore" them. Apparently, being interested in something which doesn't turn up on a news feed is an error.
And that's the charm of these sort of apps. Rather than let you find stuff for yourself, they pre-emptively decides that if they can't find stuff, you won't either and therefore it doesn't really exist. If it existed, it'd have a feed, right? And you could tag it and track it and aggregate it and rate it and rank it and send it to a friend. Bah. It's all just a big school social with stick-on name tags.