NationBuilder - The world's first platform for leaders, handcrafted from scratch to help you grow your community and lead them to action.
Flowroute - Flowroute provides direct access to telephony resources - such as calling, messaging (SMS & MMS), call routing, SIP Trunking and Communication APIs.
Crowded Communities - The all-in-one community platform.
Tatango - Tatango is a mobile messaging platform for agencies.
FUEL CYCLE by Passenger - Think Passenger builds online platforms that allow brands to connect, create and communicate with key stakeholders.
Postscript - Like Mailchimp for SMS