Using Yahoo! as Default Mail
For about a decade I have been using Yahoo! as my default mail. I found a script that could strip the email address and point it to Yahoo! Mail.
#!/bin/sh
URL=$(echo $1 | sed 's#mailto:##;s#?#\&#;s#\&subject=#\&Subj=#;s#(##;s#)##i;')
firefox -new-tab "http://compose.mail.yahoo.com/?To=$URL"
Just copy it into a text file and set default handler to your file.