I doubt that these categories will be as hierarchical and structured as proposed here. for example the pdp objects, gridflow and gem(pix and particle+related objects) are good examples for libraries.
as I wrote before, I think that coherent libraries (like the ones you said + vasp and a couple more) exclude themselves from the general external-jungle, and deserve a subcategory of their own. I imagine that the categorising process should help in grouping the objects , but to make a "transparent" and understandable structure - instead of making things more complicated. Maybe each category should have a "vanilla" subsection as well?
but zexy and cyclone are libraries where even after so many years I still don't know what some of the objects do or to which library they belong, so here the categorizations could make sense.
exactly. in the contrary of the before mentioned libraries, these are more groups of externals compassing different groups: glue, math, matrix, ...
still, I think this is much more important for documentation and pedagogical reasans than with relation to avoiding nameclashes or similar, because then we would still end up with two gate objects in the same categorization...
that is also my point (and was actually in the original discussion). but one doesn't avoid the other. in the end of http://puredata.info/dev/PdLibraries I also listed the latest efforts (that I remind of) in this respect. independently of the result of the previous section, an efficient indexing method should also be pursuited - and to remind developpers that documentation is important. maybe this section could go to another page and be discussed independently.