> billions of messages per month

Just tangential, but maybe that is part of the problem, isn't it? Napkin math tells me that esch person in the world receives every month an e-mail from you, and you're obviously just one of hundres of providers, and only half of the population actially has e-mail... I think you get the point.

E-Mail got to the point where it's actually worse then physical mail to some degree. Physical mail at least has a hurdle for the sender, and it's easier to throw away without even looking at it. The amount of low-quality mail and annoying, unnecessary notifications I receive is just at a level where I really think of dropping e-mail except for absolute becessary services.