Consumers drive market share
An interesting point to add to all this is that Google doesn't force people to use it's search engine. People are quite capable of making the choice to use it all on their own. Same goes for Microsoft and it's products. So long as everything is conducted in a voluntary manner, what's the harm? 60%, 70%, 80% of the market? Hardly a monopoly, unless we are using some weird definition of the word. From what I understand, a monopoly has 100% of the market, and the only example I can think of that has a monopoly on anything is the State.