Co-creator of Metacademy here. Colorado and I are intending Metacademy to be a “package manager for knowledge,” where you can easily find the particular thing you want to learn about (e.g. deep neural nets) without having to track down all the prerequisites (e.g. gradient descent) yourself. Basically, we’ve annotated a dependency graph for the core concepts in the field, and it uses the graph to produce step-by-step learning plans geared directly towards your goals.
Sorry if you can't reach the site. We’re both doing this as volunteers, and I guess we weren’t prepared for the level of traffic we’re getting. In the meantime, you can find more details about our high-level goals here: http://hunch.net/?p=2714