Spam trap

A spam trap is an address that no human reads, kept alive by mailbox providers and blocklist operators purely to catch senders mailing lists they never earned. Three flavors: pristine traps (addresses planted in page source that only a scraper would ever find), recycled traps (real addresses abandoned by their owner, then reactivated as traps after a long dormancy), and typo traps (gmial.com, hotnail.com, caught by signup forms with no validation).

Hitting a pristine trap says you bought or scraped a list. Hitting a recycled one says you never prune people who stopped opening. The first gets you blocklisted fast; the second bleeds reputation slowly. There is no appeal window where you get to explain yourself, and Spamhaus does not tell you which address it was.

The nasty part: traps accept your mail. They never bounce, never complain, never unsubscribe, so nothing in your dashboard points at them. You only learn they exist when placement collapses. Defense is boring and works: double opt-in, never buy or scrape, suppress anyone who has not engaged in six to twelve months, and re-verify old lists before importing them into a new sender.