Amidst all the excitement surrounding the Facebook IPO, Mark Zuckerberg, CEO of Facebook, announced a quickly and quietly planned $1 billion purchase of mobile app maker Instagram. Not surprisingly, there’s already been much speculation surrounding the timing and strategy for this acquisition. One of the aspects of the deal that became immediately interesting for the IPO was that the initial Facebook IPO filing indicated that management expected the deal to be closed in the second quarter of 2012. It was soon pointed out that this would be at odds with the news that a review of the deal by the Federal Trade Commission could take as long as 12 months or more. In an updated filing Facebook indicated only that the deal is expected to close sometime in 2012.So what’s going on here? And why is the FTC getting involved in the first place?