PostRank's analytics data is used by publishers and advertisers to determine, respectively, the popularity of content and the effectiveness of marketing campaigns.

"We're proud of what we've accomplished, and we now look forward to working with Google's team to build more useful tools for measuring engagement online, and we'll be sure to share details on our progress in the coming months," reads a message posted on PostRank's home page on Friday.

Analytics tools are crucial for online advertisers and Web publishers because they capture and slice and dice a constant stream of usage data that provides insight about how their content and ads are performing in a way that offline media can't.

For a company like Google, which generates most of its revenue from advertising, offering analytics tools to its customers is essential to its business. With the skyrocketing popularity of social media, a lot of relevant "conversations" about brands and content happen in sites like Twitter and Facebook, and in discussion forums and blog comment sections.