Open Source Software
"Open Source Software" was originally popularized by Eric S. Raymond as means to market free software in a media and corporate-friendly way. It worked, but it also introduced a subtle distinction between "open source" and "free software". Free software ensures certain freedoms that "open source" does not.
"The real disagreement between OSI and FSF, the real axis of discord between those who speak of "open source" and "free software", is not over principles. It's over tactics and rhetoric.
Where we used to be ignored and dismissed, we are now praised and respected. The same press that used to dismiss "free software" as a crackpot idea now falls over itself writing laudatory articles about "open source". And the same corporate titans who dismissed RMS as a `communist' are lining up to pour money and effort into open-source development. Our market share and mind share have both zoomed to a level that would have seemed the stuff of delirious fancy as recently as January of last year.
Have all the opinion leaders and executives who have turned around suddenly seen the pure light of the GNU manifesto? No; instead, they point to the work of Open Source advocates to explain their conversion.
OSI's tactics work. That's the easy part of the lesson. The hard part is that the FSF's tactics don't work, and never did. If RMS's rhetoric had been effective outside the hacker community, we'd have gotten where we are now five or ten years sooner and OSI would have been completely unnecessary (and I could be writing code, which I'd much rather be doing than this...)."
The main difference between "Permissive Open Source Licenses" and free software (copyleft) licesnes is that free software licenses require those making and distribution derivative works to share the source code for their modified version. "Permissive Open Source Licenses" like the MIT Software License and the Apache License 2.0 do not. Corporations can take the source code of any MIT licensed software project, modify it and sell binary versions of that modified version and keep all the source code for the modifications to themselves. That is not allowed under the GNU General Public License.
Permissive Open Source Licenses are far more popular than "Copyleft" licenses because corporations prefer them because "open source" licenses allow them to exploit and abuse people in order to make large amounts of money.