This isn't necessarily a bad thing for Google. It all depends what the FTC is asking the other as networks, assuming the reports are true, of course. No one really knows the true market share of the mobile ad networks. The only way to do this is by revenue – every other measure is flawed for one reason or another – but no mobile ad network reveals revenue – (even in secret to analysts, ask them if you don't believe us). However no one would refuse to tell the FTC their revenues, right? So why doesn't the FTC do itself, Google/AdMob and everyone else a favor and request those numbers, work out the market shares, publish it and then we can put the thing to rest once and for all. We wrote to the FTC in December suggesting this a while back with a list of the 14 ad networks to contact first (not that we heard anything of course), but fingers crossed this will be part of the investigation (assuming there is one of course). If you want to know more about as networks, this guide profiles AdMob and all the other main networks in full: http://mobithinking.com/mobile-ad-network-guide