Comment by xlii

I think I'm missing something but I've have an option to use <anything>@<ident>.domain.com for couple years now.

I don't find it that useful though and usually go with standard alias i.e. user+<anything>@domain.com

As for single sender locking - not sure how useful that is. I mean you can get github.com email or notifications.github.com so you miss half of them?