Now here’s a great way to gather totally, completely unbiased information about a potential merger: ask the companies’ competitors. Okay, so the FTC isn’t completely crazy—of course other companies in the market would have a pretty good idea what the industry looks like and what a big merger might do. But still, we can only hope the FTC will remember to take their opinions with a grain of competitive salt.

AdMob, the popular mobile advertising company, and Google, the wanna-be-popular mobile advertising company, announced the deal in November. Google gave AdMob $750M in stock in the deal. The next month, consumer groups began lobbying against the deal. Now the FTC wants both advertisers and rivals to make sworn statements about the pending merger.

The probe isn’t public, but sources say the commission is “investigating whether Google’s proposed purchase of AdMob would reduce competition in the market for Internet advertising on mobile phones.” (Kind of a duh.) Google says it’s continuing to talk with the FTC and cooperate with requests for information.

Bloomberg consulted Thomas Ensign, an antitrust lawyer, on the matter. He said, “It’s difficult to envision a scenario where this development, if true, is positive for Google-AdMob, but it doesn’t necessarily mean the agency is going to challenge the deal.”

Just over a year ago, the US Department of Justice was hours from filing anti-trust charges against the search giant over another major advertising deal (with Yahoo). Is Google pushing their luck with this merger? Will GoogleMob hurt the mobile ad industry? Will the FTC stop the deal?