I've used spamgourmet.com for many years (Literally decades, my first entry was 2003-08-07) to create disposable email address. You just make up the address "tempsite.4.username@spamgourmet.com" to create an email address for tempsite that expires after 4 uses. You can always remove this limit later. My message stats: You have 245 spamgourmet address(es). 827 emails forwarded, 28,605 eaten. The #1 worst offender for…
Because yahoo also hosted @yahoo addresses, it would have been pretty noticeable if they sold the addresses of their own users.
"EDIT:which probably correlates to the overall death of email, which is for old people, so I am told."
Still alive and kicking as the de facto passport of the internet.