Details of the FTC probe are still a bit sketchy, but rest assured that Google search dominance will be the key focus. Schmidt could use the Senate hearing to float a few trial balloons ahead of the FTC investigation.
Perhaps the biggest trial balloon from Google will be the state of search, how easy it is for users to switch and the competition from Microsoft's Bing as well as many other specialty rivals. Google is likely to argue that the search market is much broader than comScore metrics illustrate. Where most folks see search as a Google vs. Bing battle, Schmidt may note that the market is broader.
Amazon and eBay dominate product search.
Zillow is a go-to search hub for real estate.
WebMD is the search and information leader for health.
Twitter and Facebook also have strong social search components. Google is likely to note that it hasn't done so well in social networking even though its Google+ effort, which is tightly tethered to Android, has been well received so far.
Netflix serves as a search leader for movies.
Kayak is a travel search leader.
And Open Table is the point guard for restaurants.
The argument: If you include industry specific search players, the market looks much more competitive. We'll overlook that Google happens to serve up many of the links into these industry specific search players, but the argument is worth pondering.
In the end, Google is likely to argue that search is a dynamic market and point to Bing's work with Facebook and social search. Schmidt's potential bottom line: Leadership today doesn't equate to wins tomorrow and by time any antitrust litigation is settled the search business will have already changed. It's going to be interesting to watch Google's argument to fend off regulators take shape.