Online learning may not appeal to everyone; however, the sheer number of online learning sites suggests that there is at least a strong interest in convenient, portable learning options — many of which are study-at-your-own-pace. For your reference, we’ve selected 50 top learning sites and loosely collected them into the categories you’ll find below. While this is not a rankings list by any means, using a variety of criteria, we’ve filtered in some of the most popular sites in each category. Many of these sites offer free lessons; some require payment or offer verified certification for a nominal fee. Some sites offer very general non-academic lessons, others provided actual college / university curriculum course material. Whatever you are looking to learn, check out the list below before trying to wade through pages of search engine listings.