What can be done to reduce the amount of spam that is sent to an email account?

Here are some additional steps you can take to reduce or eliminate spam:

1. Use your email program’s spam filter. Most email programs have a very good built-in anti-spam feature that you can train to identify and filter spam. There are also many shareware applications available that will process all of your email first then tag any potential spam.The advantage to filtering to a separate spam/junk mail folder, rather than just deleting email identified as spam, is that that way you can deal with the filtered email when you have time to and if your spam filter misidentified something as spam (i.e. a false positive), you will not lose potentially valid email.
2. Don’t use a mailto tag to display your email addresses. If you link to the email addresses on your website using a mailto tag, then there’s a good chance that a spambot will find your email address and start spamming it. Alternate display methods include using a contact form script, munging or obfuscating you email address, displaying your email address as an image or using JavaScript to create a mailto link.
3. Use an external spam blocking service. If you are really sick of spam and filtering just doesn’t do the trick, there are several services like Spam Arrest that will filter your email based on white lists and challenge-response techniques. These services are subscription based, but are worth it to some people who are overwhelmed by spam and just want to be rid of it, even if it means that it may be a little harder for people to get ahold of them.