Communiti - Professional network for your Slack team
Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
Circle.so - Bring together your discussions, memberships, and content. Integrate a thriving community wherever your audience is, all under your own brand.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
REALITYLINE - REALITYLINE is the first OSL (Online Startup Launcher) Platform.
Bigtent - BigTent is a web-based organization and communication portal for groups.