Yeah I’m probably behind the times as I’m a pretty vanilla e-mail user but I just discovered an awesome feature in Google’s Gmail.
If you want to sign up for an account or any other thing that you don’t want to receive e-mail from simple enter your Gmail address with a plus sign and extra junk at the end of the name. For example if my e-mail address was email@example.com I could sign up for a web site using firstname.lastname@example.org and the confirmation e-mail from the site would reach my email@example.com inbox.
You can than block all mail sent to firstname.lastname@example.org so it all gets sent straight to the spam folder. Many Google thinks up some amazing features.