There is a temptation to say the problem is what my algorithm solves. Which is a very offensive thing to do, if you look at it that way. And it's almost always wrong. Curiously enough, he attributes that remark to me, as well as me attributing to him, which may say something about the nature of the evening when it was thought up. I've indicated some other areas where algorithmic progress is needed.
Image retrieval is one.
We heard yesterday about the prominent place of images in computer applications of the future. Nobody has the faintest idea how to do that. But we could all do it if only we could look at the whole video library in parallel. That is a challenge for the future, and there are many more of the same sorts. It is actually possible to give an entire talk around that subject.