How Rapportive Helps Businesses Manage Customer Relationships The company's Gmail add-on makes for a sleek social CRM tool.

Everybody knows the old saw, "It's not what you know, it's who you know." But, do you really know who you know? Probably not as well as you'd like.

Between pocketing business cards, filling up your smartphone contacts and expanding your social media connections, trying to remember who's who gets tough. But San Francisco-based Rapportive is here to help. The company's free-to-download Gmail extension automatically collects information about the person you're e-mailing, including Twitter account content, Facebook posts, LinkedIn data and any other material tied to that e-mail address. The info is displayed as a simple sidebar, usually replacing the distracting paid ads on the right side of the page.

How it Started
Founded in 2010 by University of Cambridge grads Rahul Vohra, Martin Kleppmann and Sam Stokes, Rapportive exploded in popularity with tens of thousands of users in the first 24 hours of launch. It further picked up steam with seed funding from investors like Silicon Valley's elite business incubator Y Combinator. The startup was purchased in February by LinkedIn for an undisclosed sum.