An interesting development of the idea to set up email redirections to mask your real email address comes from SpamMotel. When you set up a new email address, you can enter notes. Emails received at that address automatically have the notes prepended before being forwarded to your real email address. That way, it's simple to record when and why you set up the email address and who you gave it to, so if it gets spammed you know who to blame.
More email security resources