Microsoft has submitted a $44.6 billion bid to buy Yahoo.
This is the only scenario I can see as someone becoming a serious threat to Google. Yahoo attempted to become a content company rather than a data company, as Google is. They made a lot of mistakes, going entirely in the wrong direction, in my opinion.
This business is all about sending traffic to the most valuable source. Google understands that. Yahoo didn’t, or doesn’t. The question now, will Microsoft?