I like the possibilities that NativeClient in Chrome will open up, but I can't help think that we're going backwards... Do you remember when we used to see "Best viewed in Internet Explorer" and other crazy stuff written on websites?
Surely with Chrome/NaCl we're just going to end up with "This game/app only works in Google Chrome with NativeClient". This doesn't seem like a good thing for anyone (devs or consumers). We were just starting to get web standards right, with cross-platform coding easier than it's ever been.
I think it's highly unlikely that other browser makers will add NaCl. Certainly not Microsoft - it just makes Chrome, Chromebooks, ChromeOS more attractive to their Windows customers. I don't think they'll want to help that cause!
I love the Chromebook because it's designed for the web. It's apps are cross-browser/platform by design. It's not like Windows, Linux, iOS, Android, etc., where all the "default" apps are locked to the OS. My biggest problem with the recent take off in mobile computing is that apps are tied to the OS. This just isn't right. I should be able to pick an OS based on my preferences, and not lose all my apps, or have a restricted choice of what I can run. ChromeOS will only run things written in an open standard that work on every other common consumer OS. Do we really want to destroy this?
Don't get me wrong, I think the idea of being able to run near native code over the web is an *excellent* idea. Web-based apps solve so many problems with deployment, updates, security, etc., and being able to run performant apps in the same way is great. However, we need something open for the web, not another thing Google have gone away and built on their own and try to force upon others (just look at Wave, Dart, etc.). If they intend for NaCl to be in all browsers, then it needs to be developed openly with input from all parties, not just sprung on the world (note: I don't know if this is their intention).
Is NaCl just going to be the new ActiveX?