NationBuilder - The world's first platform for leaders, handcrafted from scratch to help you grow your community and lead them to action.
Yammer - Yammer is a leading enterprise social network used by more than 200,000 companies worldwide, including 85% of the Fortune 500, to get work done smarter and faster. Sign Up Today.
Crowded Communities - The all-in-one community platform.
MS SharePoint - Share, organize, and discover information with Microsoft SharePoint. Learn about SharePoint Online, OneDrive for Business, and Apps for SharePoint
Ning - Ning is the social platform for the worlds interests and passions online.
Communifire - Enterprise Social Collaboration Software