Desmos, a free online graphing calculator that I've written about a couple of times in the past (here, most recently), has updated their offerings again. The most significant update is a switch to HTML5 which means that Desmos will now work on iPads. The second significant enhancement is the option to register for an account and save your work online or share your work online.
For an overview of Desmos, watch the video below.
Applications for Education
As I've mentioned in the past, Desmos could be a good alternative to expensive TI-84 (or whatever the latest model is) calculators. If your school has a 1:1 program with laptops or iPads you can use Desmos in any classroom.
I got this news about Desmos from Audrey Watters at Hack Education.