Gmail Plus Addressing
Gmail has a really cool 'secret' feature which helps you sort mail and track spam-bastards: if your email is 'john.doe@gmail.com', you can send email to 'john.doe+anything@gmail.com' and it will end up in your account. How does this help? Well, let's say you visit, spamBastardFriend.com and want to sign up for a newsletter. If you give them your gmail address and you start getting spam then you can't tell who sold your address to the spam-bastards. But if you sign up for the newsletter as 'john.doe+spambastard@gmail.com' then when you start getting spam to that address, then you know who the culprit is! Then using gmail's rules you can just start trashing anything sent to that address. Using this feature, you have an unlimited supply of identifiable addresses.

The downside : many web sites simply have shoddy email validation functions that simply ignore the 1982 RFC822 spec which defines which addresses are valid. If you run into such a site, please feel free to email them and send them the link to the spec and ask them to fix their code. Also, I'm sure it's just a matter of time until spam-bastards simply start filtering all their gmail addresses to strip off the plus sign, but until then it's your friend and well worth using.

Chiaroscuro

Definition:

Italian for "light-dark." The gradations of light and dark values in two-dimensional imagery; especially the illusion of rounded, three-dimensional form created through gradations of light and shade rather than line. Highly developed by Renaissance painters.