Earlier quoted context omitted.
I haven't seen a convincing argument that Google needs social. I know they believe it, I just haven't seen anything that made a compelling case that it's actually true.
Advertising is the vast majority of Google's revenue. How vast? AdWords alone accounts for 97% of Google's earnings. The strategic vulnerability of that position cannot possibly be overstated. Along comes Facebook, which could (in theory, at least) roll out a perfectly competitive product to threaten AdWords. If social really does provide better context for advertising, and advertising within the world's prevailing s…
What Google needs, in this case, is more information on its users, which is not a particularly social thing to need.
Say Google is approaching social as an information gathering problem, and Facebook is approaching social as a users-interacting problem, then who will always win social under those conditions?