An overview of PubSubHubbub, a simple, open, web-hook-based pubsub protocol & open source reference implementation. Brett Slatkin and Brad Fitzpatrick demonstrate what PubSubHubbub is and how it works:

Raindrop UX Design and Demo from Mozilla Messaging on Vimeo.

Raindrop’s mission: make it enjoyable to participate in conversations from people you care about, whether the conversations are in email, on twitter, a friend’s blog or as part of a social networking site.

Raindrop uses a mini web server to fetch your conversations from different sources (mail, twitter, RSS feeds), intelligently pulls out the important parts, and allows you to interact with them using your favorite modern web browser (Firefox, Safari or Chrome).

Raindrop comes with a built-in experience that bubbles up what conversations are important to you. You can participate in the experience by writing extensions that use standard open Web technologies like HTML, JavaScript andCSS. Or, use the lower level APIs to make your own experience. You have control over your conversations and how you want to play with them.

As with all explorations hosted by Labs, Raindrop is an open source project and everyone is welcome to participate in its design, development and testing.