I’ve just implemented the Conduits plugin, which is what provides things like services for publishing items to blogs, social bookmarking services, repositories, citation services (etc). Its not much to look at, but it does basically follow the design wireframes. In the image below, the Radar plugin is the panel on the left; the Conduits are on the right:

The plugin drag-and-drop model uses standard URLs, so there is an interesting side-effect: you can just drag any URL from any application onto the services in FF, and it will publish them to the service. So, you can actually just use the Conduits plugin as a standalone publishing “droplet”, like so:

So far I’ve ported the del.icio.us and APP conduits from Plex, our earlier prototype system.