Content that keeps people up-to-date on the latest news, trends, contests, and facts that become hot topics of conversation.
Eg. Blogs like Buzzfeed do a really good job of this, with their "Top 10" list. This kind of content gets shared on facebook and twitter, because by sharing it, the user is showing that they are 'in the know' of exclusive knoweldge. It makes them look smart, and now they have social currency.