Just a small addition to what has been said above (not meant as insult to anyone who posted here):

The idea of downloadable content was not of Microsoft. But they'll most likely be capable of making it reality.

The first console which offered that sort of downloads was the Sega Genesis. They had a test project running - the "Sega Channel". Downloading games and demos was possible via TV and Modem (I think).

The idea most likely has been there before, I don't know.
The first console featuring online gaming was Dreamcast. Many people don't know...
Surfing the WWW with a console was possible with the netlink package for Sega Saturn, but it was not very widely spread. I think it was US only. Not sure if that was the first console with online capabilities..?