Two techniques which appear not only to currently be 100% successful at protecting email addresses, but are likely to remain so for some time. The first technique uses Javascript to obscure the address, the second hides the email address in an image. Harvesters are unlikely to begin interpreting Javascript any time soon and even less likely to do the OCR required to pull an email address from an image.
Use a tool to create your own Javascript email address obscuring script. Enter your email address in the box and press the “OBSCURE!” button. You can then copy the resulting script and place it anywhere on your webpages where you want your email address to appear.
The second technique involves hiding your email address in an image. You can use any popular graphics program to encode your email address as a GIF, PNG, JPEG, or other standard web format. Because the current crop of spambots is not able to interpret the contents of images email addresses displayed on a website in this way are likely to remain protected.
It should be noted that both of these techniques are likely to remain sound for some time to come. Harvesters that interpret the Javascript on every page they encounter would face a substantial risk of getting stuck in infinite loops or crashing due to malformed Javascript. A spambot that can do OCR is even less likely. Not only would such a harvester need to download images, creating a significantly higher bandwidth load than spammers currently face, but it would then need to process every one of those images. This is likely beyond the current computing power of a legitimate company like Google; there is virtually no risk spambots will develop this capability in the foreseeable future.