Google Chrome dev channel hits v7 -- get ready for native code in Web apps!
So, what is Native Client all about? It's Google open source tech which allows native code (the kind of code which powers your favorite desktop apps) to run inside your browser. Assuming that browser is Google Chrome, of course, because no one else sports NaCl support yet. Native code in the browser should mean the arrival of Web apps that truly compete with desktop apps in terms of performance -- which could be a big boost to things like online media converters and photo editors. At the very least, you'll be able to play Quake in Chrome.
If you want to see Native Client in action, Google has a gallery of NaCl demo ports you can check out -- or at least you're meant to be able to check them out. Both Chrome dev and Canary responded with a "missing plug-in" message when i tried to load them, even though Native Client was enabled (as you can see in my screenshot).
The dev channel update was actually quite a major one, though it mostly contained bugfixes and cleaned up code. The full log of revisions is available here.
update: as reported in the comments, you need to add the --enable-nacl flag to your shortcut. I've done that, and the demos still don't load, however. The missing plug-in message did disappear at least...