I think it may be a valid question, but certianly gives you very different information about a potential employee. "Move Mt. Fuji" is only slightly vauge -- the only problem is that it is huge. It's a good question when you want to see if someone is easily troubled by the enormity of an otherwise do-able task. "Help the victims of the Indian Ocean tsunami" is much more vauge. It would be a decent test of the ability to start narrowing down an assignment, which is an important skill. I suspect almost all projects start out as a poorly defined idea, like "improve what people about to make a purchase think of our product". There are a lot of ways to approach that -- changing marketing vs changing the product, for example. Asking the suggested question provides information about a canidate that can help judge if they'd provide a viewpoint missing from your present team, and is thus useful. However, it provides very different information then the moving the mountian question.