[inthewoods]

This is the fundamental issue with all advertising-based models. Eventually, they all run into the problem of having to continue to grow. The only way to continue to grow is to display more ads, thus compromising the user experience, which starts the downfall. AOL was a great example of this. Google seems to be heading this way.

Google's original values were the ability to provide better search (common answer) and be fast (less common answer) - both of which were a complete contrast to the Alta Vista and other search engines. I could easily see Google facing disruption from a new player - but I don't think it will be another search engine. Probably a paradigm/systemic shift.