I think Google is great for finding new, rapidly changing information, but it is pretty weak when you are looking for authorative information that doesn’t change every couple of weeks.

Searching Google for PHP error codes, for example, frequently turns up recent forum posts by people who didn’t bother searching for the answer first. A few comprehensive pages explaining the error codes would be much more useful than “I’m getting this error; please fix it” posts.

History is another example of a subject where fresh content mostly shouldn’t be found at the top of the search results.

The point is that, instead of trying to recognise the value of new content faster than Google, there is space for a search engine to specialise in content that doesn’t need to be fresh.