My question too. Given that I can get a list of open source projects that I can work on for free with GitHub Explore[1] I am wondering what this provides me that is worth any money, not specifically $30. To take it one step further, why should I pay you for a list of free projects, when I can get paid to work on projects with other sites like Rent A Coder[2]? The list of features implies that I will effectively only get screencasts that I don't get from github repositories and depending on your language there are lots of places to get those too (ex [3]).
Don't get me wrong, I am all for monetizing, but I greedily want something if I am going to pay for it.
I'm guessing that Marc will try to curate the projects so that you learn a lot in as little time as possible. You could work on rent a coder instead but presumably on that site, most projects will be web based CRUD apps whereas I'm imagining that these projects will help you grow as a developer.
Don't get me wrong, I am all for monetizing, but I greedily want something if I am going to pay for it.
[1] https://github.com/explore
[2] http://www.rent-acoder.com/
[3] http://devblog.avdi.org/2013/06/21/a-list-of-programming-scr...
EDIT: formatting