On a website I was working on recently I addressed this problem by slightly obfuscating the email address in the HTML: <a href="mailto:user(at)example(dot)com"

On a website I was working on recently I addressed this problem by slightly obfuscating the email address in the HTML: <a href="mailto:user(at)example(dot)com">Email us</a> I then wrote some JavaScript to modify the href attribute to be the real email address. So for the vast majority of people, they'd get a working mailto: link, but for the rest, they'd get a mailto: link which required them to replace (at) and (dot). Not perfect, but I suspect it stops the vast majority of bots.