Cool - when we send out our newsletters to users, about 70,000 total active emails, we get a solid 1000 bounces in the first hour or so. Bounces decrease each time we newsletter, since we flag users with a bounce_count, and if it reaches 2, or the bounce is a 5xx (permanent error), we don't email them anymore. But, 1000 full stack loads in an hour on our mailserver would crush it!