Google's Social networking Building Blocks

Here's an article that has useful information on Google's recent acquisitions pertaining to social networking.  According to the article, it has made

five acquisitions in the field: SocialDeck, a mobile social gaming company;Angstro, a social networking search application; Like.com, a social fashion store; Jambool, a social gaming virtual currency; and Slide, a social game maker. It also has a large stake in gaming giant Zynga.

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Think about these as part of the exploration-exploitation axis and what they could mean in its positioning against Facebook.