It's definitely going to be interesting no that the cat is out of the bag and Google decides to go after Facebook for the campaign. The legal ramifications on this will be something to watch!
I've seen many people take the approach of "leaking" information in order to slander a competitor, but this wasn't even a competitor (for the most part). If there was a case there about the scraping of content or pulling of data etc, Facebook should have gone directly to Google (or court) in order to get an injunction to stop the exposure of information.
I'm sure this story will only pick up speed as the weeks and months go by.