Mailinator architecture

Paul Tyma (who now works at google) talks about the architecture of Mailinator. I love its simple design.. its fundamentally a stripped down java SMTP server which holds all the emails in memory, so disk IO is not a problem.

He says that 99% of emails received are not read, so he compresses them to reduce the memory footprint; to limit spam an aged hashmap is used based on IP and subjects. He obvious used the KISS approach... nice.