Ask HN: Is Google reaching its limit?

I could argue Google has made only superficial improvements to it's search engine over the past 5 years. They tweak the algorithm, they change rankings, and they add "instant" search.

I get the distinct feeling that Google has already reached, or is quickly approaching a technology barrier, where they simply don't know how to improve search any further before their competitors catch up. And this is guiding their decisions to enter so many other industries and make so many acquisitions.

What do you think it will take to make a search engine several orders of magnitude better than Google than is today? (is NLP-based A.I. required?)