[paulrr]

I never understood why people rely on the + trick to determine the source of new spam. Wouldn't a smart spammer / list-seller simply strip the suffix from all @gmail.com addresses?

[mbertrand]

I've thought the same thing since I encountered this trick a few years back. My guess is that most email providers don't allow the use of a "+" in the address and as a result its viewed as a fringe case and not accounted for.

[danielweber]

It's not a valid way to test for illicit spam, but it's a good way to help keep honest people honest.

There are researchers who make brand-new addresses and put them in various places as a tripwire for spam.