Well, there are two hard problems in computer science, cache invalidation, naming things and off-by-one errors.
Extensions aren't bad, but you need to find them in the first place, and if all you've got is a single, non-hierarchical identifier... I'm aware that more elaborate namespaces like e.g. CPANs also can cause confusion, i.e. if they're not followed and you end up with modules all across the tree, but with a bit of community support the benefits still could outweigh this.
Imho. npm really isn't very good for finding libraries. I generally google for them instead and check out the first few hits on github. Perhaps that's why the writer of the article was so exited about the github monoculture.
assemble-less, baidu-less, buildr laessig, less, less-bal, less-clean, less-cluster, less-context-functions, less-features-connect, less-less, lesscompile, lesscw, lessup, lesswatcher, lessweb, style-compile, styles, watch-lessc, wepp
Number of packages is far from a perfect measure of how much interesting and important work is going on in a community.