If it looks familiar, maybe because it has similarities to the Facebook feed. But there are differences. For one thing there are two main tributaries of content, and for now you must toggle between them. One is a pipeline from your social graph, a cornucopia of social content from friends, family, colleagues and acquaintances. Whatever they share an item — and are okay with you seeing it — the link, picture, or comment might appear in your stream.
The second is called Sparks. In this feature, users type in subjects of personal interest — “sparks.” Then Google streams items about that subject. The content that Google pulls into your Sparks stream is different from the results you’d get if you put the same term into the search engine.
“It’s focused on getting stuff that’s fresh and social and fun. We’ve tried to tune parameters to get something that’s engaging,” says Andrew Tomkins, a top search engineer who joined Google after stints at IBM and Yahoo. The signals that Google looks for in determining Sparks content is freshness, a visual component (videos will rank highly), and the degree to which the content is virally spreading on the net. (Tellingly, the Google News group has moved into the Emerald Sea division.) In other words, Sparks tries to deliver the kinds of thing you want to share with others, and Google hopes that its users do just that.
“Sparks is essentially the stuff that flows to you through the interest graph and the stream is the stuff that flows to you through the social graph,” says Tomkins. Basically, Google thinks that its expertise in search quality will make the items in both of these feeds more relevant, interesting and diverse than the stuff people see in their Facebook feed.
Update: The Next Web pulled together the videos Google has released that explain and show exactly how Google+ works.