Simple Calculator Suggestions

I made a basic calculator. I'm thinking about making an RPN calculator down the track.

http://www.a-calculator.com/

Do you guys have any suggestions for features or anything else?

First Apple made it necessary to have an Internet connection to install almost anything for Mac OS X 10.7 and later, then Microsoft made it necessary to have an Internet connection for just about anything in Windows 8, even just to play audio CDs in the Windows 8 Music app (which would be your only choice if there was only Microsoft, unless you have Windows 8 Pro), then, as IGN said, "the next Xbox console will need to be fed off a constant internet connection"?
That's it! I'm not using anything more from Apple or Microsoft!

That's very anti-progress of you, Anon.

Does it do everything the http://www.Wolframalpha.com bot does?

>>4
N.. No. I'll add natural language processing one day. Just give me a few decades.