"Commonly used" depends on who you ask. I use it all the time to help me look up units. It may not be 1000 calls/day, but it's still useful. Also the #/calls ca

"Commonly used" depends on who you ask. I use it all the time to help me look up units. It may not be 1000 calls/day, but it's still useful. Also the #/calls can be expanded with enterprise Mathematica. It was added in Mathematica 8 (see bottom of http://reference.wolfram.com/mathematica/ref/WolframAlpha.html http://reference.wolfram.com/mathematica/ref/WolframAlpha.ht..., "New in 8"). Disclaimer: I work for Wolfram Research