[paulsutter]

I like the idea for length-limited emails, it's original and clever. Unlike shortmail, this limits people who aren't on your whitelist.

Automated response email (good catch Rudism) could be handled via some sort of separate inbox or UI organization.

One counterintuitive thought: this may work even better within corporations. My external email isn't bad, but company internal email has always been a few hundred messages a day for me. A length limitation might put the onus back on the sender to be efficient.