The interesting Gmail social-context plugin, Rapportive, has been acquired by social-media for professionals company LinkedIn.

Rapportive creates plugin software that provides context-sensitive social-media information on top of Gmail’s user interface. As a result, it works as a sort of highly immersive address book that brings a lot of social-media information to the front when replying to e-mails. With Rapportive active, it’s possible to see recent tweets and other information about the subject of the e-mail giving a great deal of context for conversation.

This makes them perfect for LinkedIn’s mission of connecting professionals and probably guided the decision to acquire Rapportive.

While neither company has revealed how much was paid, it’s rumored the price ran somewhere around $15 million in cash, reported by TechCrunch reporter Alexia Tsotsis early February. The acquisition was acknowledged late February by executives at both companies with Hani Durzy, LinkedIn’s director of corporate communications sending out an e-mail to that effect.

“Rapportive does a great job at delivering relevant information in a platform that is universally used by professionals — email. It’s very much in line with LinkedIn’s mission to make professionals more productive and successful in their careers,” Durzy wrote.

In order to quell any customer concerns that the partnership might affect their product negatively, Rahul Vohra, CEO of Rapportive, is quoted on his blog displaying great excitement about the acquisition and the future vision of the social e-mail plugin.

“Since we accidentally launched, we have relentlessly pursued this vision, integrating LinkedIn, Facebook, Twitter, and your address book right into your email,” he wrote. “During our partnership with LinkedIn, we got to know them very well. We found a great overlap between our visions.”

No doubt, the partnership between LinkedIn and Rapportive will provide a huge benefit for customers of both. Conversations on all forms of media often shift between them—although rarely seamlessly—but it’s often useful to know what a person is currently saying while addressing them in an e-mail. With Rapportive’s service, a businessman could be speaking to a potential client and see that they’re currently complaining about a particular product on their Twitter; they could then use that to guide conversation in e-mail. It removes the necessity to remember to check all the social media outlets for a contacts current mood before addressing them.

Information overload is about having too many avenues to bring information to a person, but the inability to organize or prioritize it. With an overlay that brings the information to you via context, and provide it when you’ll most likely need it most, it takes away part of the organization stress and gives a better insight into the person you’re talking to.

As long as this can be done without pressing extra buttons, as Vohra said about his service, he wants it to become second nature or something “you don’t have to remember to use.”

Just like Twitter updates and connections, LinkedIn updates and connections provide a whole other context to entertain thoughts and provide information while communicating.