Yes, that is standard subaddressing but not all email providers support it (I've never heard of a Microsoft Exchange server supporting it). One problem with it

Yes, that is standard subaddressing but not all email providers support it (I've never heard of a Microsoft Exchange server supporting it). One problem with it is it exposes your real email address. Another problem, as the Wikipedia article notes, is there are a lot of inputs with poorly written validation that won't accept '+' as a valid email address character (they often only allow a-z, '.', and '@'). https://en.wikipedia.org/wiki/Email_address#Subaddressing https://en.wikipedia.org/wiki/Email_address#Subaddressing