Digital Marketing Guide: The Social Web
-by Abbey Klaassen and Beth Snyder Bulik

http://adage.com/digital/article?article_id=135590

Isn’t the entire web social these days?

To an extent, yes. If 2008 was the year everyone — and their grandmas — joined a social network, then 2009 is the year those networks’ social graphs spread their tentacles beyond their borders to other sites across the web. Already it’s common for many sites, including major news sources and entertainment properties, to have commenting and sharing features. So we admit the social web is a pervasive concept. But there are several interesting newer developments at Twitter and Facebook, as well as in the widget space and the app world.