In case the term is unfamiliar, it is applied to sites that generate loads of content, plenty of it-all-adds-up traffic through viral distribution, and loads of page impressions for advertisers. The critics suggest it's lacking in depth and riddling the Web with low-quality data ultimately for attracting ineffective advertising.
The challenge is that this content is very friendly for search engines because of its frequent filing and optimization. The bigger challenge is for Google and others to find ways to elevate higher-quality material.