> There was a time before SMTP. That is why I mentioned common format (headers + message) and 'mostly' SMTP. But for early email, allowing users to email some

> There was a time before SMTP. That is why I mentioned common format (headers + message) and 'mostly' SMTP. But for early email, allowing users to email someone at a different computer wasn't an issue of profit. 'Cloud' companies don't want you to use another company's products. Google doesn't want your docs stored on Dropbox. That issue didn't exist with email, and if you look at something like Facebook messages, you can't send a message from a Facebook account to a Myspace (or whatever else) account. That, more than anything else, is going to inhibit 'cloud' growth.