Despite fact that Federal legislation (the CANSPAM act) made it illegal, harvesting email addresses from web using automated robots remains alive and well.
Spammers who need fresh email addresses release software spider programs that comb Internet and suck email addresses off Web pages, guest books, and anywhere else you might post your email address.
Once they get your email address, spammers will trade it around like 5th graders with a new pack of Pokemon cards at recess and you can expect avalanche of email to begin flooding your inbox.
In order to combat this still rampant practice of stealing email addresses from websites and sending people email they don't want, following tips should help protect you.
** Break It Up **
Obviously best way to avoid getting picked up by an email harvester is not to post your email anywhere on anyone's website (including your own).
If only way someone can get your email is if you give it to them, that creates a similar situation to operating with an unlisted phone number.
If telemarketers can't get your phone number, they can't call.
If you must post your email address, post it in a way that a robot won't recognize it as an email address. Instead of posting YOURNAME@YOURDOMAIN.COM, you can put YOURNAME (AT) YOURDOMAIN.COM and then, in parenthesis, put (replace AT with @ to email me).
Though it seems like an extra step for legitimate email, you'll find it a very effective technique.
** Use An Image **
Currently, online spiders (ANY spider, including search engines) cannot read text that appears in a graphic or picture. If you must display an email address on a page, then do it by typing your email address into your favorite graphics program and saving image as a .gif or .jpg. Then post image onto your web page so people can see email, but spiders cannot. This too creates an extra step for people because they must type in your email address, but it's an effective solution if you must display an email address on your own website.