WolframAlpha: sophisticated online calculations resource
29th June 2009
If you ever need to glimpse at the properties of the Poisson distribution with lambda=0.16, or find the factorial of 6163338 (as a gamma function), then Wolfram|Alpha is a perfect tool for you (unless you have some math package at hand).
The motto of Wolfram|Alpha is Making the world’s knowledge computable. Basically, it is like Mathematica plus a growing corpus of factual numeric data, plus a system to interpret user’s input. This is a nice online reference and computation platform.