...also, google's not going to take this lying down ;)

Why I say that... Open Graph is part of Facebook's strategy to use its 400M-user social network as leverage to take over indexing and navigation of the web, and serve ads with it.

Navigation of the web has been almost entirely Google's territory, because of Search (which also equals 90% of their revenue, from AdWords ads).

Therefore, Google has to counter Open Graph somehow...