I've been using a catch-all email domain for years where anytime I give out an email address, the local part is a description of the party receiving the address (e.g. bestbuy.com@mydomain.com).
If I receive spam at a particular address, it's easily blocked and I know who leaked it.
An interesting side effect of receiving email from so many different addresses to the same inbox is that I often receive the same spam to multiple addresses simultaneously. This is easily caught by spam filters and so I never have Spam in my inbox. It also makes identifying false positives in my Spam box easy because they usually stand out against the repeated subject lines so it's a simple game of which one of these is not like the others.
If I receive spam at a particular address, it's easily blocked and I know who leaked it.
An interesting side effect of receiving email from so many different addresses to the same inbox is that I often receive the same spam to multiple addresses simultaneously. This is easily caught by spam filters and so I never have Spam in my inbox. It also makes identifying false positives in my Spam box easy because they usually stand out against the repeated subject lines so it's a simple game of which one of these is not like the others.