Abhishek Jain asks Stack Overflow about the differences between zlib, gzip and Zip, and gets a fascinating and very insightful response from none other than Mark Adler. I particularly like the comment Adler made when the OP asked about referenecs for his answer. I am the reference, having been part of all of that. This post could be cited in Wikipedia as an original source. This, to me, is a perfect example of the enormous impact of open source and free software libraries developed in the 80s and 90s have on modern-day computing.