I knew that you could add dots anywhere in your email address, but I didn't realise you go do "username+otherthing@gmail.com" and it would come through.
So, "username+websiteyoususpectmightsellyouremailaddress@gmail.com" would let you know who's selling your details.
In Russia they read your pdf to you..
(Yandex, fookin brill pdf viewer).
That's because all emails are filtered through a central intelligence-gathering bureau. They read them to you if you ask, otherwise they just read them to themselves, so there's not use wearing a tin-foil hat.