That's a funny take, considering my experience. I know some email servers are slow, of course, but they don't have to be. When I worked on Gmail, the majority of Gmail-to-Gmail messages were delivered in under a second, and not because they have a special internal protocol; even such internal messages are sent over SMTP. But Gchat was never that fast. 1 second was considered fast delivery by Gchat but it was long tail slow for Gmail.

>90% of mails are delivered really in a couple of seconds, but yeah, turnaround could be quicker. That's why in the longer run we hope to skip the store-and-forward mechanism and instead deliver mails directly by IMAP server to IMAP server.

I doubt most email servers actually take anywhere close to 30s to process an email. I suspect most of the delay is the sending server queueing and email client polling intervals.