The browser plugin Rapportive, which lets users check their social networks within Gmail and Google Apps, is rumored to have been acquired by LinkedIn, according to AllThingsD.
"Sources familiar with the negotiations said LinkedIn offered Rapportive 'low teens' of millions of dollars worth of cash," writes AllThingsD. "The deal has not officially closed yet."
The way Rapportive works is it grabs data from social sites like Facebook, Twitter, and LinkedIn and lets users view what's going on in a sidebar next to their e-mail inbox. Rapportive also has its own social network based on users' e-mail contact lists.
"You can immediately see what people look like, where they're based, and what they do," Rapport says on its Web site. "You can establish rapport by mentioning shared interests."
According to its Web site, Rapportive launched in 2010 and now "pumps over 20 million lookups" through their system every month. Email tool startups similar to Rapportive include Xobni, WhoSent.It, and Mingly.
LinkedIn went public last May, and in the fall it reported a profitable year so far. The social-networking site also hit 100 million users.
LinkedIn declined CNET's request for comment about the acquisition of Rapportive.