Search is getting more social. Anyone who is watching the way that Google and Bing present their results and determine rankings on keywords can see this.
Social media sites like Facebook, Twitter, and Pinterest (not to mention Google+, which is trying to seamlessly tie in search with social) are all becoming more prominent in search while continuing to improve their own internal search engines.
These two facts are pushing us towards a collision course where search marketing and social marketing are becoming the same overall concept.
Via Antonino Militello