It will be interesting to see if google open up the chromecast protocol to third parties.

My guess is that they won't --- I expect the margins on this are low or non-existent, and it anyway would be very unlike google to attempt to make money out of this as a hardware product.

It's clearly a strategy to sneak the web onto the TV. There seems to be little incentive for google to extend it to mobile apps, where they make substantially less from advertising.

Also, I have no idea why Apple haven't released a similar dongle purely for airplay streaming. Seems like a no-brainer for them.