I'm not really sure how this is a personal knowledge hacking tool, but mini-lessons or articles emailed to me everyday might be interesting. I signed up for paradoxes.
It's an awful lot of courses to pick through when you're signing up. Maybe just offer the five most popular to start?
I also second this. A good approach may be to show 3-5 subjects (e.g. Philosophy, Startups, Architecture) and highlight one of the courses that would be the best beginners course. So if I'm interested in philosophy it's very easy to just see immediately where I could/should begin and click just one button. Going in to feature creep here but; as I just signed up I haven't completed a course yet, obviously, so I don't know what happens then, but it would be great (for retention etc.) to be recommended a natural next course to take as well. Dumb it down for the user even more. Actually what I would do is to have a button in the last email of a course that would read "Continue with GREATEST PHILOSOPHERS IN HISTORY". So just one click and I would be in the loop again.
I definitely got in to a "oh this is nice.. and this too.. and these two would be cool..". At the same having the full catalogue of courses available is good of course, but don't overwhelm the first time user.
I would test having the "popular courses" feature, or something like proposed above, just under your headline actually. So it's super easy to see what the site is really about without even having to scroll. That would show off the kind of content you have and even though your name is Highbrow, it might not be clear if you're teaching out nail painting techniques or philosophy when I just read the headline and the feature list you have.
I'd suggest the 5 best quality courses, and a "More.." button. The "buzzfeed" comment elsewhere leads me to believe the other guy picked one of the courses that was not curated as well as what I chose, which is the basis of my suggestion.
I've received one highbrow email thus far, and I am happy for reading a good quality blog post instead of having to sift through serps and junk blogs for myself, and also to learn about some new resources in my area of interest. I totally get the one thing at a time, 5 minute per day commitment, I think it's a great idea.
It's an awful lot of courses to pick through when you're signing up. Maybe just offer the five most popular to start?