On the front page of my website where I display a mailto link, I also have GMail and Yahoo specific compose links:<p>"Email: mymailtolink (Compose with GMail/Yahoo)"<p><a href="https://grepular.com/" rel="nofollow">https://grepular.com/</a><p>I wrote some JavaScript code a while back which would automatically detect if a visitor was logged in to GMail, and would replace all mailto links on my page with GMail compose links instead. I never put it live on my site though as the process of detecting if a user is logged in to gmail is pretty dodgy. In case you're interested in the code, or the detection process:<p><a href="https://grepular.com/Abusing_HTTP_Status_Codes_to_Expose_Private_Information" rel="nofollow">https://grepular.com/Abusing_HTTP_Status_Codes_to_Expose_Pri...</a>