Think of a research tree, then. Or more formally, a simple directed graph. Nodes can be "on" or "off", meaning you (claim to) have or not have the skill that node describes. A nodes can be a prerequisite for other.

This can be taken many ways, but one obvious example would be a "sequences comprehension tree". One node per part of the sequences, with the parts that part is based on as prerequisites. You could claim a node to express confidence you've understood (or even agreed with?) that particular part, track your progress, and if you could publicly share your progress along this sequences comprehension (or any other) tree, you could also show off.

This could be done in JavaScript fairly easily, and it'd be awesome I think. Anyone want to code it?