The Berkeley Software Distribution, first released in 1978, was a very important early open-source project. The second version, released in 1979, included the vi editor. When Sun Microsystems formed, they incorporated BSD into their OS, SunOS. In fact, people on the internet have asserted that the TCP/IP stack for most operating systems, including the first stack incorporated into Linux and into Windows 95, was copied from BSD's stack. Since sharing source code is an effective way to increase the chances that two different systems will be able to interoperate on the internet, this TCP/IP stack from BSD (whose creation was funded by the US government) probably materially sped up the growth of the internet.

The original BSD license, which is quite close to the BSD license used by many open-source project today, was created because the owners of BSD (the University of California) believed BSD had to be placed in the public domain because its creation was funded by the US government, and the US government is prohibited by law from copyrighting its creations. Actually, they did not release it into the public domain, but the license they chose is very close to "public domain" in that the restrictions it imposes are very light.

Before 1993, most of the software used for communication on the internet was either explicitly open source (i.e., under the GPL or the BSD license) or "informal open-source", meaning that it did not come with formal license terms, but its source code was available, and it was widely believed that it was unlikely that anyone would try to stop you if you modified it or redistributed it.

BSD was encumbered by AT&T code & licenses and most definitely not open source until something like 1992 and BSD4.4-Lite (which really begat the open source *BSD releases) didn't come out until 1994.

Yes, and that does not contradict anything I wrote. Particularly, the BSD license long predates 1992, and Sun Microsystems took advantage of that license to sell computers in which BSD constituted a large fraction of the software starting in 1982.

The fact that there was a decade or more of legal uncertainty over whether AT&T could use the courts to stop the distribution of BSD by the University of California certainly had an inhibitory effect, but never actually stopped the distribution of BSD by the University, and did not prevent BSD's source code from being redistributed freely or from being incorporated into most operating systems capable of connecting to the internet even before the legal uncertainty was resolved in the early 1990s.

That's not how what you wrote read. You may have meant that a BSD license existed in '82, but you implied the BSD modified Unix operating system was generally open source long before it really was. The fact that many manufactures secured separate licenses (for which they paid Berkeley a lot of money) is irrelevant. The simple fact is that the truly "free" BSDs did not exist before the early 90s and the resolution of the dispute between AT&T and Berkeley. Full stop. End of story.

GNU everyhing, just go to gnu.org, and remember that what we refer to as "linux" is mainly the os kernel, most of the user space programs, libs etc. are GNU projects.

I'll get behind the toolchain (GCC, as, gdb, etc) as a game changer, but "everyhing"? Please...other than GNU rewrites of BSD 4.3 userland programs (not hard), most of the projects on gnu.org happened after Linux became ascendant if not dominant. And of the major pre-Linux projects, how many are still indispensable? How about the colossal waste of resources behind GNU Emacs? GNU could have recreated Genera, and done it better, and really changed the world for all that went into it and it did nothing more than create a fetish for a tiny and declining group of people. We don't even need to go to Hurd; it's punchline to a software project joke right there with Duke Nukem.

The GNU development toolchain (GCC, etc). Without a solid, free, complete, self hosting development environment, literally nothing else you mention would exist.

I think jQuery should be on the list...it has had a big impact on front-end programming, and it powers over half of the top 10000 sites.