Exactly. My own domain is on Fastmail. I have an alias for every sites I have account in (Amazon, eBay, Pocket, ...). If I got spammed using an address I know e

Exactly. My own domain is on Fastmail. I have an alias for every sites I have account in (Amazon, eBay, Pocket, ...). If I got spammed using an address I know exactly where it came from, advise the sir and create another alias.