A good strategy to keep your inbox spam-free is to use a different email address every time you sign up for a service. It takes only a minute to setup a new address that forwards all emails to your main account, but it will save you tons of time when the spam starts rolling in. You can easily disable the forwarder, if it gets flooded with spam, and your main address will remain safe.
An added benefit is that you can find out how the spammers got a hold of your address. If your create an address like firstname.lastname@example.org and you only use that address to create a Twitter account, you can be sure that all email addressed to email@example.com is either coming from Twitter, from someone Twitter gave/sold the address to or from someone who gained illegal access to Twitter's servers.
Today, I received the first spam emails addressed to the email address I used to join the WarriorForum. This means the WarriorForum was either hacked or someone working for them is in bed with the spammers.