Just an FYI: You can do this with an email

Email allows "+<suffix>" to be appended to any email.

The usual case is something like "user+testing@site.com", or "user+bills@site.com".

It's a way to auto-tag your incoming mail. You can use one of these "+" suffixes on a per-app basis and then add a spam filter to permanently burn one of them if you get spammed.