Your best defense against spam is not getting on a spammer's list of valid emails. There are four tactics you can easily employ:
Use disposable email addresses. Using your "real" email address anywhere on the Web puts that address at risk for being harvested by spammers' robots. To avoid this problem, you can configure a disposable address to forward to your real address and then dispose of the temporary address when it becomes the subject of too much spam.
Watch your checkboxes. On the bottom of almost every form on the Web is a box or series of boxes that, when left either checked or unchecked, leads to spam filling the old inbox. But be sure to read carefully. Checking some checkboxes indicates that you do want to get offers from sponsors and partners, whereas checking others indicates that you don't want to receive these offers.
Disguise your email address in newsgroups or chat. Spammers employ special programs that cull email addresses from chat rooms, forums, and newsgroups. To combat this practice, you can use a disguise. How? Insert something "extra" into your email address that can be deciphered easily by a human but not by a robot looking for email addresses, such as using delete_me somewhere in the address. Humans reading your email address would naturally remove the "delete_me" part of the email address.
Use a disposable address on your home page. Use a disposable address in the mailto: links on your home page instead of your real address. Then, if the email comes from a legitimate stranger (a new customer or reader of a book, for example), you can reply with information about your real email address for future correspondence. If the email is spam, you can immediately disable the disposable address and replace it with a new disposable address. This will prevent any spam that was sent to the old disposable address from getting delivered to the real address.