I'm sorry, but you are so grossly wrong in your statements that the only valid response is a bit of a fisking. Normally I'd prefer not to respond this way, but I've already engaged you, and I can't really let this much misinformation stand.
> Both have sandboxes (ActiveX since Windows 6.0, IE7), both have restricted APIs, both run native code.
ActiveX is a general purpose object API and has no sandbox at all. IE 7+ on Vista+ can instantiate ActiveX controls in a weak sandbox via low-integrity mode, but to imply it's comparable to the NaCl sandbox is just comically ignorant. NaCl validates the nexe's conformance and its subset of x86 instructions before it will run it (in that way being very similar to Java and .NET CLR). And NaCl runs entirely in an outer, system-level sandbox that denies all system and object access.
In contrast, IE's low integrity mode lets you read anything the user can, exposes massive chunks of the system as attack surface, and provides various writeable locations. On top of that, all non-trivial ActiveX controls in IE implement brokers which run fully outside the sandbox--something that's not even possible with NaCl.
> PNaCl is equivalent of silverlight which is cut down CLR.
Nope. And making that claim begins to underscore just how little you know about this.
> More performance - I doubt it. CLR+JVM is pretty much up there. The moment you add any virtualization, trap code or translation layer to native code via NaCl which you will require for security, there is going to be overhead which will knock it inline with a VM architecture. Startup time might be less - that is it.
Virtualization or trap layer? That's not even close to how NaCl works. It's really sad that you couldn't be bothered to read a one-page explanation of before you launched into this completely wrong-headed diatribe. Please, start here next time, so your trolling can at least be superficially informed: https://developers.google.com/native-client/overview
> Better security - that's a lie. Virtualization on any layer never gave anyone better security. It's throwing stones in glass houses. The only hard security boundary is at the MMU/page table. As NaCl grows, you will see it break.
Once again, premised on your total ignorance of the subject matter. Come back when you have at least a basic knowledge of the thing you're criticizing.
> No-one getting sued? I'm sure the EU will have something to say when no other vendor implements it and Google uses it to leverage market share, much like Microsoft did in the late 90's and early 00's.
I'm sure there was an attempt at making an argument in this last line, but mostly it just seems to be randomly scrambling for scary sounding words.