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.
Google Buzz, the company’s answer to Twitter and other real-time social sharing services, launched in February, and the API was opened up to the public in May. The firehose was made available late Monday, and it publishes everything Buzz users are sharing (except for Twitter tweets). Google says it’s Buzz developers’ most-requested feature. Previously, you could run searches on Google Buzz activity, but there was no way to subscribe to a feed that publishes what everyone on Buzz is talking about or sharing at any given moment with very low latency.
Some Google partners were involved in the launch, and they’ve prepped some apps to show off what the firehose can do. Have a look at Buzz Mood, an app (obviously inspired by our old Twitter favorite Twistori) that tracks emotional keywords like “love,” “hate,” “believe,” and “hope,” showing you the most recent posts containing those words in a constantly refreshing stream.
Also check out Gnip, the social aggregation service that collects user activities from Twitter, MySpace, Buzz, Facebook, Digg and over 100 social sites. Gnip republishes all these feeds in multiple formats and combinations, and it makes everything — now including the Buzz firehose — available to its customers via its own API.
All of the public activities in Google Buzz are published through the firehose using PubSubHubbub, a protocol that’s being widely adopted on the social web. PubSubHubbub, which was created inside Google and is now being developed into an open standard, pushes out updates to apps as they happen. It replaces the old model — one that’s been the standard for many years — where an application repeatedly asks the publishing server if there’s anything new.
PubSubHubbub is more efficient and provides the app with notifications the instant they happen. It’s not the only data format for real-time publishing: also have a look at RSSCloud.
Google is turning on some other API features as well, including a comments feed for comments left by each user, and a similar feed for “likes” made by each user.
Google is using Activity Streams, another emerging standard on the social web, to wrap all of the activity data. The AML-based Activity Streams format allows for notifications of things like comments, likes, and favorites. So, subscribe to the Google Buzz feed for so-and-so, and you’ll not only be notified that so-and-so posted a video, but also that his friend liked that video, or that an hour later, somebody else left a comment about it.