Alison has 15 million learners in 195 countries. The courses are free to learners. They make their money through advertising and merchandize.
Codecademy has a community of 45 million learners and offers courses in all the major programming languages and development platforms.
60 million learners from around the world come to learn skills from more than 200 of the world’s top universities and industry educators who partner with Coursera to offer courses, Specializations, certificates, and degree programs. Hundreds of free courses give you access to on-demand video lectures, homework exercises, and community discussion forums.
Founded by Harvard and MIT, edX is home to more than 20 million learners, the majority of top-ranked universities in the world and industry-leading companies. As a global nonprofit, edX is transforming traditional education, removing the barriers of cost, location and access.
Khan Academy has millions of users. It offers practice exercises, instructional videos, and a personalized learning dashboard offering lessons in math, science, computing, history, art history, and economics.
Hillsborough Public Library offers subscriptions to several online learning plaforms including: Universal Class, Lynda.com, Mango Languages, Tutor.com, and Learning Express Library (test prep)
Udemy offers over 7,000 free courses as well as many thousands more of low-cost courses in a wide-variety of categories.