What is interesting to me is that it gives you the answer, but not the source. For calculations, there isn’t really a source anyway. I don’t cite that 2+2=4. However, I do cite the population of Germany. So how are we supposed to know it is right? On the other hand, I think showing similar information you might not have asked for is cool.
Turns out this isn’t a big thing to worry about. WolframAlpha gives you the source of it’s answer. For example, I searched for swine flu. It told me the scientific name along with the number of cases and deaths over the last couple of days. In addition to a nice pop-up and PDF to export the data, it has a “source information” link at the bottom. This shows the data set used to derive the answer along with other resources one might be interested in.
As a source for learning, I think this is pretty cool!