Using HTTP headers and default browser protocol handlers provides an opportunity to rediscover the usability and simplicity of the mailto protocol.

Over the last decade it's become unsafe to use the mailto protocol on a website due to e-mail harvesters and web scraping. No one wants to put their e-mail address out on teh envelope-mailboxInternets because two minutes after doing so you end up on a trillion SPAM lists and the next thing you know you're changing your e-mail address.

But people still wanted to share contact information, so it became common practice to spell out your e-mail address, such as l.macvittie AT F5 dot com. But e-mail harvesters quickly figured out how to circumvent that practice so people got even more inventive, describing how to type the @ sign instead. For example, you can send me an e-mail at l.macvittie SHIFT 2 But that's inconvenient and isn't easily automated, and eventually the e-mail harvesters figure that one out, too.

You could use contact forms instead to hide the e-mail address, but that's not really sharing and it isn't convenient for the person trying to get a hold of you. Like many folks, if I have a need to contact you I’d like a record that I did so and contact forms rarely provide a copy of the message which makes managing communication more difficult. It also affords spammers an easily automated method of submitting spam. What you really want is to be able to share your e-mail address and avoid the automated e-mail harvesters. Some folks suggest using CSS tricks that manipulate selectors to hide the e-mail address, but the problem with this is that it (1) doesn’t automatically launch a mail client and (2) the e-mail address is still in the text of the page, it’s just located in a different place. Some techniques use pure CSS and pseudoclass selectors and others use CSS to expose the actually e-mail address that is “hidden” in one of the HREF attributes, often the title. But in both cases the address is still in the page – or in an external CSS file which bots might pull if they’re following all links - and a simple regular expression search will find it easily enough.