Honestly, I don't think there's that much value in the data. Most of the big social gaming companies probably have most of that data anyway from scraping the social graph -- if money is in the data, they haven't been mining their data properly.
There's more value to create for whoever manages to monetise the data. But will it be Facebook? Or will it be someone else? Doesn't seem like that will matter for an IPO. An IPO will benefit certain large investors regardless of what happens to the company long term. And they will cash out quick.