These Web 2.0 sites can often spike the traffic to an otherwise unknown site overnight by drawing attention thousands or tens of thousands of visitors. They are communities unto themselves, spreading good word-of-mouth about the things they see and experience online.
Of course, with success comes problems. Payola 2.0 is taking place, with unscrupulous (some would argue) marketers paying some of the heavy influencers on these sites for positive reviews of the sites in question.
With any WSJ.com article, it’ll only be available for a short time, so if you’re interested, read up on The Wizard of Buzz now.