This seems like an amazing concept and I have been thinking of it ever since I saw KhanAcademy knowledge tree.

I can see this being combined with Arbital's Lens (Same thing explained in multiple ways - from a simple explanation for a 10-year-old to a rigorous explanation for a mathematician)

I always considered this the best way to actually progress in my learning and I still see it as the next big thing after Wikipedia, once it's done correctly.

No I have not seen this, but it looks awesome and like a great place to start. This structure is pretty much exactly what I envisioned at a high level. It would be even more useful if there were a finer degree of granularity between concepts, and each vertex actually directly linked to a video. I think the killer feature for a partially ordered learning resource is going to be keeping people within the ecosystem (i.e. watching embedded videos or reading embedded articles/guides/etc.) so they can grind out on your website, not repeatedly have to go to other websites where they may get distracted or become reluctant to return to the original.

Really appreciate the links