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.
Tatango - Tatango is a mobile messaging platform for agencies.
MS SharePoint - Share, organize, and discover information with Microsoft SharePoint. Learn about SharePoint Online, OneDrive for Business, and Apps for SharePoint
Postscript - Like Mailchimp for SMS
Communifire - Enterprise Social Collaboration Software
Flowroute - Flowroute provides direct access to telephony resources - such as calling, messaging (SMS & MMS), call routing, SIP Trunking and Communication APIs.