In a CNET.com interview, Google technology director Craig Silverstein was asked when he thought advanced artificially intelligent search (such as “search pets” or agents) will happen. His answer:

I think that understanding language is kind of the last frontier in artificial intelligence, and then talking to a computer will be just like talking to a reference librarian, because they will both be equally knowledgeable about the world and about you.

The big difference, and this is where the search pets come in, is that the reference librarian will understand emotions and other nonfactual information that even a fully intelligent computer may have trouble with.

In terms of timing, I typically say about 200 to 300 years. I think it is probably closer to the 300th year end of it. But if it ends up being closer to the 200th year, I would not be around in any case, and I will not be able to have anyone gainsay me.