Courseroot - Biggest online course database on the web
Stealthy: Secret Messenger - Chat anonymously with friends & strangers
Alcamy - Free, open self-learning platform. Learn & teach anything.
Roomvine - Chatrooms for real life venues, neighborhoods and events
CurrencyStack - A free modern currency data API for fintech apps.
Jodel - What is Jodel all about? Jodel is the community that shows you what's happening in your area in real-time.