People as me all the time for use cases, examples, and best practices around using social media in a business environment - for a variety of business purposes: Marketing, customer support (internal and support team collaboration), new product development, HR (new hires, alums, recruiting).
I've pulled together an initial list of examples that can be seen publicly - there are many others that are behind firewall that I can't link to. This is an initial list but I would be happy to extend the list - just email me at rhappe at idc.com.
Hope you find this useful.