I've got an Adwords campaign running and I need to track (in Analytics) how much I'm spending to get a mailto click on my page. What's the best way to track that?
You need to set up the mailto click as a conversion. I would change the link a bit so when clicked to takes the user to a page where they fill out an email form. When the form is submitted, this is where your conversion code should be. Also, the form should encourage more emails versus just using a mailto link. Once you set up your conversion, you can do lots of tracking in AdWords and Analytics.
Either way, you need a page you can put your conversion code on. It can't be the page with the mailto link because you don't know if the visitor has clicked it yet. It has to be some page behind the link.
maybe a quick redirect page? that way you can put the conversion code on the intermitent page, then have it shoot the user to wherever without anyone the wiser...