Neat tricks on Gmail
Recently I got an email address to First.Surname@domain, which is odd because my e-mail is actually FirstSurname (no "."). It seems like if Google can't find an account for an address it looks for a similar one. I tested it with FirstSur.name and Fir.stSurname and they both work too.
This is really useful, as when I give out my e-mail address people often forget whether to include the dot.
Another neat trick is that Google supports the obscure "+" operator. This allows you to add a sub-name to your address: username+sub@domain will be delivered to username@domain with the "+sub" left in. You can set up rules for the results.