I'm going to have to write a lot more about this at some point, but briefly, I think the Web is moving us from a Judgment-oriented culture to a Consensus-oriented one. By that I mean that we are substituting the opinions of many for the selectivity of a few authorities.
This is obvious in the broadest sense of the term publishing. It used to be that you had to have editors and publishers find enough value in your work to deem it worthy of publication. Now anyone with a Web site can publish, and it can look as authoritative as the big money sites.
I've also seen Web contests in which competing writers (or illustrators or whatever) try to get all their friends, relatives, acquaintances, co-workers, etc. to vote on their work, so they can beat out all the other contestants whose friends, relatives, etc. are less cooperative. There have always been contests in various creative pursuits, but they seem to have proliferated in this "click to vote" world.
Some people choose their iTunes music and other downloads based on the ratings these have received, rather than based on music reviews or other supposedly authoritative opinions.
To some extent, the media have always been consensus-driven. Producers look at sales figures, Nielsen ratings, etc. to steer their resources. But it's become much more direct. Not only are the media providers looking at these figures, but buyers are relying on public opinion much more directly and more heavily than in the pre-Web days. This is how viral marketing and memes work.