In the US at least, you must prove that the consumer was harmed in order to have a successful antitrust complaint, and that's going to be pretty hard with google. With microsoft, it was a pretty clear pattern, ie rebates to OEMs to thwart competition. And more recently, disallowing users to change their default browser. Instead, with google, you can bid/get ranked high and you're still able to compete. You can install chrome and change the default search engine easily, etc etc. Google has been pretty careful about avoiding mistakes Microsoft made. And at the end of the day, if you don't like google, you type in "bing.com" and lo and behold, you're using another search engine. You could not (at the time at least)just install a competing OS within seconds.