If you use Gmail, you’ll love this tip — it sorts your mail for you.
“If you use Gmail here is a killer tip. Use custom addresses for newsletter subscriptions by adding a + to the end of your gmail address and some custom text. For example, if firstname.lastname@example.org wanted to signup for Groupon he could use email@example.com. The email gets delivered to the same inbox but now you can use a filter that looks for that address.”