Otherwise known as the internet.
Those who create content are usually highly motivated about particular issues. Blogs and podcasts tend to be short and pretty specific. For me, this means I get several discrete lessons on particular subjects, but the relationships between the subjects are not always readily apparent.
The order of a book, or the chronology of a classroom do not necessarily impart any more knowledge, but the knowledge there is presented in an order we are more acculturated to. In addition, I have a suspicion that certain nuances are better understood by different senses: I find listening to N.T. Wright far more interesting than reading him, for example. A good chunk of the information is in his voice, in his tone, and that's where I can get a good understanding of where he is coming from.
Obviously there are subject matters that lend themselves to this kind of learning and those that don't. I suppose I could try to learn calculus randomly, but I think it would be harder than the classroom experience. As for political science, psychology, and philosophy- well I wouldn't mind taking every minute I spent in those classes back because I can find better stuff on the internet.