Indeed even the best search engines are only going to be able to answer that question if it is stated somewhere. Hakia can do that. However no search engine is going to be able to figure out the answer by, for example adding up all the times he appeared in a given year. So if someone wrote somewhere "john mcain was a guest on the daily show seven times in 2008" hakia should be able to give you an answer.

There's a bigger problem there. For the current year, the quantity could change. Old, incorrect values would outweigh new, correct values. So, you still wouldn't get the right answer.

"Who, what, when and how do" queries can be answered with current AI techniques but "how many" queries are much harder.

I have not looked at Freebase in a while, but, theoretically they could -- assuming all the info is populated in freebase.

It'd be interesting if search engines allowed a rudimentary query language for stuff like that.