NaCl is a side-long step in the right direction, but it gets almost as much wrong as it gets right: * You have to know what platform you're targeting (ARM vs.

NaCl is a side-long step in the right direction, but it gets almost as much wrong as it gets right: * You have to know what platform you're targeting (ARM vs. x86), which eliminates the browser/JS advantage of architecture abstraction * You have to recompile specifically for NaCl, which removes any potential benefit on binary reuse As others have noted, NaCl is closer to ActiveX-reborn than it is to a generic web runtime architecture.