Meetup - Helps groups of people with shared interests plan events and facilitates off line group meetings in various localities around the world.
deface - removes facebook from facebook so you can chat with friends without distractions.
Eventbrite - Discover Great Events or Create Your Own & Sell Tickets
Facebook Messenger Kids - Safer and More Fun Video Calls and Messaging
Bigtent - BigTent is a web-based organization and communication portal for groups.
Taku - A social app that turns your words into images