Exactly, the problem with e-mail is that it is not RESTful. Nothing is hyperlinked by default. Sending a huge binary to a group of 100 people results in 100 send messages including the huge binary, even though maybe 50 people actually did something with the binary attachment. But the same problem is sending a mail to a large group of users. For example if Amazon sends an e-mail to its user the complete content is transmitted N times. If with a RESTful architecture they only had to transmit the URL to that message with a subject. Users that are interested would open the message.
To rephrase how I understand your comment, an email sitting in your inbox would just be a link to a glorified webpage hosted on Amazon's servers, where everyone can click through to that.
That's a pretty interesting idea. Emails from, for example, Amazon are pretty much just HTML files being sent to each user already. Obviously you would be able to customize the links sent as emails so each user can see the information they want being pulled from the database so it looks functionally like an email right now. Seems like it would be a nice bandwidth-saving protocol. It would also get around the issue of email storage and file attachment limits. It would offload the cost of receiving a message away from Google or the user and shift that burden back to the sender. Someone could easily tell how effective their newsletter is because it would count as a page view. The page could even be opened "within" Gmail as an iframe (or whatever people are using these days).
