It seems the author of this article is confusing the delivery of physical JavaScript libraries (as separate files) with number of libraries used.
"Five of the 13 publishers I looked at included at least 20 JavaScript libraries while the most libraries included by a social network was 4, which was Pinterest"
For example, he claims 4 on Pinterest, but I quickly looked and one of those files, called: bundle.e3e1df0f.js which has compressed MANY LIBRARIES IN IT (975 KB worth, without gzipping), like JQuery, underscore, backbone, require.JS, Google closure, etc...
Just because a site is packaging up 30 JavaScript libraries into one file, doesn't mean it's not using all these libraries.
I'll also add, that I think a lot of the 3rd party tracking libraries don't really work if you bundle them up and deliver them with your own code, which is why they're usually referenced separately.
"Five of the 13 publishers I looked at included at least 20 JavaScript libraries while the most libraries included by a social network was 4, which was Pinterest"
For example, he claims 4 on Pinterest, but I quickly looked and one of those files, called: bundle.e3e1df0f.js which has compressed MANY LIBRARIES IN IT (975 KB worth, without gzipping), like JQuery, underscore, backbone, require.JS, Google closure, etc...
Just because a site is packaging up 30 JavaScript libraries into one file, doesn't mean it's not using all these libraries.
I'll also add, that I think a lot of the 3rd party tracking libraries don't really work if you bundle them up and deliver them with your own code, which is why they're usually referenced separately.