It’s the end of the year, so here come the usual self-serving tracts from tech companies about how well they’ve done by doing good.

Case in point: Facebook’s fb latest blog post touting the traction of the open-source software projects the social media giant has backed.

Facebook, like Yahoo yhoo , Google goog , Yelp, and older-school companies like IBM ibm , take growing pride in turning over key software code to the open source “community” of developers. Even Microsoft MSFT , long viewed as the enemy of open-source development, has focused on making its Azure cloud computing platform a hospitable place for open-source software, including different flavors of the Linux operating system.

MORE: Yes, Apple is running open-source software.

Once software code is open-sourced, developers can download it for free from the Github or other code repository, improve it, and return those changes to the broader community for reuse.

This is an interesting dynamic for companies that made their living building and selling proprietary (non open-source) software, because they typically cannot charge for open-source code. But they can sell commercial-grade support for that software to business customers who are not comfortable relying on a team of outside developers to support the software they use in-house. Commercial support is a paid service that will (allegedly) come with guaranteed response times and other features, whereas community support is more freeform.

The beauty of the open-source model for commercial companies is that if the code they share is valuable, it will get picked up and used widely, leading to a bigger community, more potential users for higher-level software that can be sold, and more kudos for the company that contributed it to begin with.

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On Facebook’s win list this year? WordPress, the popular content management system used by many news organizations and blogging sites (including started using React, a Facebook-backed JavaScript library that developers can use to build clean user interfaces, i.e. the screens users interact with when they go to a web site. Netflix, the big media streaming site, is also now using React, according to Christine Abernathy, the developer advocate for Facebook’s open source team who wrote Tuesday’s Facebook blog post and who telegraphed the contents on this blog post Monday.

Such new household names as Airbnb, Dropbox, and Netflix nflx are using the Presto query language, which lets users ask questions (aka make queries of) multiple distributed data sources.

WATCH: Check out the software the presidential candidates are using.

It is no exaggeration to say that the open-source movement has revolutionized how even commercial (i.e. paid) software is developed and sold. Big data companies like Cloudera and Hortonworks, based their work on Apache Hadoop, a framework for managing distributed data sources that was originated at Yahoo YHOO .

Facebook, it could be argued as one former colleague did, has done more for the open-source faithful lately than even Google or Yahoo. It built the Cassandra database which helped move Hadoop along.

And Facebook’s decision to open source everything has probably pushed others to do the same in order to attract talent. After all, all the cool developers want to work on open source now.

As for which of the Facebook-inspired projects get the most rave reviews (as measured by stars posted on Github), React was the company’s first project to attain 30,000 stars this year, after hitting 10,000 in 2014.

This post was updated at 2:23 p.m. EST with a link to the Facebook blog post.