A recent up-and-comer web destination has been http://www.digg.com.
Promoted as a democratic competitor to Slashdot, Digg has differentiated itself by the fact that the community (in true "Web 2.0" form) determines the visibility of stories - as opposed to the paid editors of Slashdot - voting stories up by "Digging" them. Those stories that are voted upon enough get boosted to the "front page" (or the front page of one of the sections, like software), vastly increasing their exposure, while the stories that don't catch on quickly degrade to irrelevance in the Digg world.
The problem I have with Digg is the same problem I see with many community-driven sites: It isn't a large body of domain-knowledgeable, unbiased, critical evaluators spending needed time to evaluate the worthiness of submissions, but instead is largely a bunch of fly-by visitors that are often going with whatever has the feel of an appropriate story, going with whatever the herd thinks (in situations like that, where voting is free, people often express their feelings superficially, feeling obligated to contribute to the democracy but preferring to do so with minimal effort). Groupthink in action. This same principal applies at Flickr as well, where the most interesting pictures are the pictures from people heavily involved in the community, and that have already appeared as interesting (e.g. most of the viewers aren't talent scouts out watching the raw talent - instead they're watching the big leagues and commenting on who's good). It's not that those pictures aren't interesting - there are often fantastic pictures in that set - but rather it's just that they are selected from a very small set of the available Flickr photos.
This same problem appears in Slashdot moderation, where it's quite easy to game the system. You can ensure that your comment will get moderated up to Score:5 by following a couple of simple posting rules.
This is possible because many of the people with mod points simply want to exhaust them as quickly as possible - this is actually encouraged by Slashdot - so they moderate up whatever has the feel of a prototypical Score:5 comment. Even if it isn't based on the referenced article, makes a nonsensical point, or is a brutally obvious karma whore, it will be Score:5 in no time.
Of course Digg might not be ideal, and even though the highest ranked stories are examples of Groupthink herding in action, it's not like the editors at Slashdot do a better job. Most of them don't even read their own site (evident by the incredible number of duplicate stories. I visit Slashdot once or twice a day, yet even I manage to immediately spot the duplicates that people who get paid to do this fulltime amazingly can't), and many of the stories they pick are dated and of marginal interest to most of the community.
My ideal situation would be a composite site - I'd love to see the best of both worlds, where it isn't a select group of apathetic employees doing the selection, nor is it a random group of herding individuals engaged in groupthink, but rather it's my own anointed group of selectors. This could be accomplished in a Digg type setting by allowing me to agree or disagree with the selection of a story. As it learns my opinion of stories, complex associative data mining could be used to build a set of stories agreed to by a set of individuals with similar selection criteria. I don't want to have to manually select "friends" or build any web of trusts, but rather it should be easy to implement based upon my tastes correlated with the tastes of others.
In a simplified form, what I'm talking about is implemented by http://www.stumbleupon.com/, albeit in web toolbar form.