Social media trends in 2012: The 10 biggest headlines of the year | The Social Media Learning Lab | Scoop.it
Excerpts:

Pinterest was the social media success story of the year, offering a more visual alternative to Facebook and Twitter that synced neatly with ecommerce and affiliate marketing.

Facebook continued to dominate and Twitter grabbed most of the headlines (although not always for the right reasons).

Twitter clamped down on third party apps to pave way for more ads,

LinkedIn added follow tools and bought SlideShare, while Salesforce boosted social CRM for clients buy snapping up BuddyMedia.