As a Mainframe programmer I was Disappointed when I looked at the page. I was hoping this would be a web based Mainframe emulator possibly running public domain versions of OS/360.
I've toyed with the idea of setting up mainframes-as-a-service. I would probably just run the various Linux distributions running inside Hercules and abstract it away as cleanly as possible. You'd never get the performance or capacity, but you'd get a cheap, easy emulation for coding and small-scale testing. It's been a while since I had time for a side-project but I'd still love to work on this.
I know, because I am the system programmer who set this up internally at my company.
[0]: http://www-03.ibm.com/software/products/en/ratideveandtesten...
I wonder if you could run X11 in a browser. You'd have to get around the fact that it couldn't accept client connections, but otherwise, it seems plausible.
http://www.youtube.com/watch?v=6zJ8TNcWTyo
It will basically do the same thing as Mainframe2 except it'll be open source and you'll be able to run it (the server) wherever you like. I've been working on the X11 support quite a lot over the past few weeks... Hopefully the public beta will be ready soon.