Caveat
This is Mac only and you need Mailmate and Keyboard Maestro. Mailmate is not essential as you could build a macro for any mail client. This one however, does use mailmate.
Explanation
I’ve created a Keyboard Maestro shortcut that uses the DL API to send the Subject of an email and URL to the email to Dynalist (via curl). The Subject becomes the content and the URL the note.
Why? I use Dynalist as my todo list. When going through my emails, I now only need to press a keyboard shortcut and the subject and link to the email land in my Dynalist inbox. I can then move it to wherever I want and open the email by clicking the link in the Dynalist note field when I start working on it.
Thanks to the great people at the Keyboard Maestro forum who helped me achieve this.
You can download the macro here.