Amazing idea this. Back in the day at university I had a go with Fontographer and haven't really touched it since. This is similar but online. There are limited shapes so you don't have anywhere near the control you get when created characters in illustrator but it is still impressive. The tools are intuitive and the keyboard shortcuts make it feel like a desktop program. The fact you can download your typeface or view a gallery of others is a great idea. It's the equivalent of, say, Vecteezy but with a stripped down version of illustrator on the site to allow you to create the vectors there and then.
Check it out at: http://fontstruct.fontshop.com/