Stack Overflow - Community-based Q&A part of the Stack Exchange platform.
Udemy - Online Courses - Learn Anything, On Your Schedule
The Answer Bank - The Answer Bank is the UK’s leading question-and-answer site.
Adobe Learning Manager - Adobe Learning Manager (formerly Adobe Captivate Prime LMS) is easy to setup and helps in delivering engaging learning experiences in a personalized manner across devices.
Blurtit - Blurtit is a Q&A website. You can ask a question or answer on any question.
Moodle - Moodle is the world's most popular learning management system. Start creating your online learning site in minutes!