Gmail Tips

Dave has his Gmail Tips - The Complete Collection in one place and makes some very helpful and useful tips. For instance, I didn't know that you could use username+something@gmail.com, replacing something with tags so you can track your email. I do something very similar at the moment with my helsby.net domain but this will be handy for gmail. I've actually started using this for my testing now - any emails with +test now go directly to my testing label category and do not appear in my inbox.
I have a couple of invites left if anyone wants one btw.
Update Not all the tips are valid now - the unread label doesn't work as thats included automatically but its still worth the 15 minute read to find out something new.