Ask HN: do you use theirdomain@yourdomain.com when registering accounts?

I don't know if there is a name for the practice, but when I register a new account somewhere I tend to sign up with the email address foo@mydomain.com where foo = their domain minus the TLD.

Recently it's helped me see that a large email marketing firm has been hacked as many versions of the same spam message have arrived in my inbox sent to specific email addresses. It also prevents some of the cross-federated identity detection some "services" like RapLeaf try to do.

However, it becomes a pain with Gravatar, single sign on and places where email addresses have a provenance.

On that last point, I recently signed up for Qwiki, using the email address qwiki@mydomain.com. I also decided to sign up my girlfriend as well. Long story short, she got an invite and I didn't. :(

If Qwiki used any social media tools to discover "valuableness" of a given user from their email address, hers would have had great provenance and mine would have nothing.