Email addresses with a "+" are not parsed correctly

[eluser]johnwbaxter[/eluser]
In gmail there is a very handy feature using the +.

If you sign up to a website you can put [email protected], when gmail receives it it assigns the label "websitename".

A great use for this is if say you sign up to a website and then you start getting spam, you can find out who has leaked your e-mail address as it will be going to [email protected] and you can go to them and be cross.