Dragonfly is particularly interesting because it uses the "Scope Protocol" (http://dragonfly.opera.com/app/scope-interface/ http://dragonfly.opera.com/app/scope

Dragonfly is particularly interesting because it uses the "Scope Protocol" (http://dragonfly.opera.com/app/scope-interface/ http://dragonfly.opera.com/app/scope-interface/) to access Opera. In other words you can remotely debug a page on a headless machine running Opera. Or, if other browsers implemented the Scope protocol then you could debug them with Dragonfly too. On the flip-side you could build your own debugger for Opera which used the Scope protocol to access what was happening in the browser. I think this is something that the industry really needs, to decouple browser debugging, from browser plugins. I'm glad Opera are making this step.