Need to encode many addresses? use the automated spam protection service.
Getting form spam? try FormSmarts.
As with a regular email link, clicking on a spam-protected link launches an e-mail client window. So, unless you select the challenge option, visitors will not even notice anything unusual.
A limitation of the previous approach is that it relies on a valid and complete program: given an appropriate tool, it can be executed and reveal your email address. We can resolve this by making the program computationally incomplete with regards to the information we are trying to hide. The program now does not contain your full email address, only part of it.
However, since we would (obviously) like legitimates users of your website to be able to contact you, we still need to store the missing information somewhere. Somewhere readily accessible to them, but not to crawlers. Here we store this information on a picture. Reading it on the picture is reasonably straightforward for humans, but it is a problem very hard to solve computationally.
RSS Anti-Spam Service Update Notification