I agree that their search engine and ad platform could be classified as monopoly. However I disagree that their actions have been anti-competitive in any manner.

They have a huge chunk of the search market but you can still use very good search engines like bing, yahoo, ask, aol or the awesome duckduckgo.

Google is continually tweaking and improving the design, speed, results and features of their search engine in an effort to stay ahead of the competition.

The reasons that people don't use the other engines are not because of google being "anti-competitive" but rather due to them offering a superior service.