Anyway, what does this have to do with android?
I think it has quite a lot to do with the future of Google software. A Unity NaCl port automatically includes Linux support, because Google is doing the last mile work to local APIs. Unity had completely ruled out a Linux port previous to this because of the API fragmentation problems. Now Unity works anywhere Google cares to make NaCl happen. How long until Android tablets, and eventually Android phones, support NaCl? It can't be more than a few years away.
By the way, "now" is Chrome v6 at the earliest, and probably later for Unity support.
In the abstract, Native Client is all about fully utilizing your local hardware on the web, which is going to be a pretty broad spectrum of devices (phones, tablets, laptops, etc). It will seem weird in a few years if websites
can't take full advantage of your hardware, in the same way that 3D in the browser still seems a little strange today.