It may help first to think about what your goals are in a more general sense than directly about what specific bits of information you might want to assimilate. For example, you say that you're not a computer programmer professionally, but do you want to be? If so, one way to think about these issues is first to figure out generally what type of position you would be interested in applying for, and then pursuing and strengthening the requisite skills. For instance, the other day I composed a list of subjects that I'd be less than comfortable discussing in an interview, and so built myself a syllabus of material and a rough timeframe for e.g., basic XML proficiency, review of certain algorithms and O(N) notation, C/C++ review, etc.

If you're not planning to pursue software as a career, perhaps you'd be better off just thinking about the kinds of problems you like to solve. A diligiently curious person -- as you seem to be -- will find it very difficult to exhaust the realm of digital possibilities, so follow your muse.

I think it makes more sense to begin from a more abstract, goal-oriented perspective than to take something like "the 7 stages" too seriously, as the latter assumes that the reader is actually interested in learning the minutia of every aspect of Perl coding. Its ranking doesn't take into account the interests or professional emphasis of the programmer in question. I find that I fit no stage well, but only a vertical sampling from nearly every one.