Spammers use dictionary hacks too. For instance, if your name is John Smith, then you may have
[email protected]
All a spammer has to do is email to john.smith, john.jones, mary.smith, mary.jones, etc. and some of the emails will come through.
The only thing to do against this is to have some random email address like
[email protected]. But this is horrible and unmemorisable, so most people don't. Google's spam filter is about the best there is on webmail systems though, so hopefully any spam will end up in there and not clutter up your inbox.