Change made to this tag wiki (2/14/15)
The current about box at the top of the math-software tag page currently directs users with questions regarding WolframAlpha to consider posting on Mathematica StackExchange instead. Here is the full statement:
For help with mathematical questions arising from software such as Maple, MATLAB, Mathcad, Pari/GP, R, and so on. Consider posting questions about Mathematica and WolframAlpha onto Mathematica StackExchange instead. For GAP, SAGE, and MAGMA, use computer-algebra-systems.
However, the What questions can I ask about? page over on the Mathematica StackExchange indicates that WolframAlpha questions are specifically off topic.