> This is not even remotely comparable to what most email providers do. They insert ads around the service, but never actually alter the content of the email
I thought someone might bring this up. This still isn't comparable to altering the actual content of your mail. The ads, though displayed with all of your genuine mail, are still discreet items and are noninvasive. This type of advertising is quite similar classic snail mail, where junk mail is mixed in with regular mail.
http://news.cnet.com/8301-1023_3-57594819-93/google-starts-p...