While it’s slowly been heading this direction for a while, for me LinkedIn has been really the last (mostly) decent place to maintain a professional network and share and explore interests. I think part of the reason is (most) people are not hiding behind pseudonyms, which (mostly) keeps things civil.
I’ve stayed with them because it’s still biased to being a professional networking and employment site. Moves like this will have me cancelling premium quickly. I don’t want Facebook’dIn.
The obvious game for them to add is Diplomacy. No better way to forge deeper professional connections! ;-)