Think Photoshop, and all of the other programs that come with it, and more, online.
Unfortunately, the software is still very much in beta and of the twenty or so tools only two are currently active. Most people (me included) only have access to the first tool, actually. Nonetheless, you can still make some pretty cool stuff with what's available. This is something that I made this afternoon:
The suite is still quite buggy, but it shows excellent potential. If anybody wants an invite, I may have a spare one for a short while.