Yammer

Yammer is an enterprise social network established to foster team collaboration, empower employees, and drive business transformation.

Yammer can be accessed through the web, desktop, and mobile devices including iPhone, iPad, Windows Phone, Android, and Blackberry, enabling a “virtual office” that employees can plug into while on-the-go. Additionally, Yammer can be easily integrated with other systems such as Microsoft SharePoint, creating a social layer across all enterprise applications.

Co-founded by David Sacks and Adam Pisoni and now part of Microsoft, Yammer serves more than 7 million users, including employees from 85 percent of the Fortune 500 companies.