Every single public message on Google Buzz, the content-sharing Platform from the search giant, is now available to any developer. A similar, if much fatter, pipe is available from Twitter, but only for large partners paying big bucks. Accessing the "firehose" is about the same any other API, which makes it an easy way to get a lot of content quickly.
Webmonkey explained the terminology and its usefulness:
Google has added a feature to its Buzz API that publishes every activity as it happens in a single Feed. On the social web, this is commonly called a "Firehose"--a syndication feed that publishes all public activities as they happen in one big, fat stream. It’s a lot to sift through, but app developers consider a firehose essential for incorporating real-time search results and real-time "trending" lists from a particular social service into their creations.
We love it when APIs (or new features of existing APIs) launch with example applications. It's even better if there's example code. Google provides both here, with the fun and simple Buzz Mood app. It simply looks for specific phrases (ie, "I love", "I hate") and ranks the general mood on Buzz. It runs on Google App Engine (our Google App Engine API profile), so the example code is written in Python.
To drink from the Buzz firehose, you'll need to use PubSubHubbub, described in the video embedded below. Rather than traditional Polling, you can subscribe to a hub and receive a "push" to your server when there's something new. The Buzz Documentation's real-time updates section shows the specifics of using PubSubhubbub with Google Buzz.