In a nutshell: we aggregate user activity from dozens of social hubs, and use that data for analytics, benchmarking and so forth. So, if you think of links as "votes" as the core-data for Google's PageRank.. Than at PostRank we're extending that graph with dozens of other gestures: bookmarks, likes, comments, etc, and building our ranking on top of that! I'm sure you can imagine the myriad of ways of how that data can be applied in different contexts.

Super excited to join Google and take it to the next level!

One of the reasons could be its founder/CTO, Ilya Grigorik. Check out http://www.igvita.com/. He is brilliant.

This is why press releases usually include boilerplate describing each company.

They look at your social media posts and provide analytics that measure how engaged people are (commenting, liking, retweeting, etc).

I used PostRank when I built a reputation & SEO engine. Their product is amazing. It extracts all social signals it can find in the web. My guess is that Google, trying to scrape all social signals they could, decided to hire those guys to help them. One more weapon in their fight with Facebook.

An old but descriptive article about them in Financial Post : http://www.financialpost.com/story.html?id=1554656