YouOS: A Web Operating System This new release, a product of MIT Labs, is quite a marvel of engineering. It's Ajax, natch, and JavaScript/DHTML heavy, natch. But it also is an actual operating system, with all of the major applications you expect: Mail, Chat, RSS, File, Browser, Stickies, and more. My only gripe is they've assumed that the world is better off with Microsoft's design decisions than Apple's when it comes to the details of the GUI: Placement of close/maximize buttons, presence of menus in every window (Gahhhrrr!), the windows explorer file browser model (Blaaaccchhh!).

And then there's the small insult on the YouOS home page:

You are using Safari 419. Warning: Your browser will most likely not work with YouOS. See our FAQ for more information on browser compatibility.

It's insulting because, as it turns out, YouOS worked perfectly in Safari--at least the parts I tested--and the YouOS development team has made the questionable decision to do Mac OS X testing in Firefox rather than Safari.

I wrote to the developers asking them to think about changing this, since testing Firefox on the Mac is pretty redundant of Firefox on Windows. They should be testing Safari on Mac OS X, and including Opera on Windows.

The good news is that this group has done a top-notch job at building an actual, live operating system in JavaScript, CSS, and HTML (probably some Java in there, too). The interconnected layers of applications seems to be very sophisticated and polished. I've signed up for a developers account, since they apparently are inviting developers to build applications (in JavaScript) for YouOS.

Just as if it were an actual OS!