Spammers use a number of methods to collect email addresses off the Web. One common method is to use "harvesting software" to extract email addresses from websites. These types of software spider the Internet for the sole purpose of finding and collecting email addresses.

The simplest solution to prevent your email address from being harvested from your website is to remove all email addresses from all of your web pages. This is the most extreme solution, but if you need to get your visitors to send you information, then use a form. If you don't put your email addresses directly on your site, then the spammers cannot get it using their harvesters.

If you still want to have your email address on your website, you can use a javascript like this to break up the address in to small pieces that are assembled again in your visitor's browser. While this isn't a guaranteed fool-proof method, it is an effective one in most cases.