Signing up for a new service? Gmail recognizes the + sign now, so you can create an alternate version of your email and monitor if you begin to receive spam to that new address (it'll all still go to your main Gmail inbox.) So if your email was usually [email protected], you could sign up for Hulu with [email protected] and keep an eye on your usual Gmail inbox for spam mail sent to that alternate address. Then you know who sold your contact info to marketers.This trick works as many times as you'd like, so you can add a + sign with a specific word to create infinite alternates that will all go to your main Gmail inbox.