You could have a greasemonkey script that puts a 'continue this discussion on [site]' button and then auto-cross post on a click. Even also put auto put a comme

You could have a greasemonkey script that puts a 'continue this discussion on [site]' button and then auto-cross post on a click. Even also put auto put a comment in that says 'I'd like to continue this on [site], please join me there'.