This is a badly written article full of FUD. It's written by an angry backend engineer, not a lawyer, and it shows.<p>He goes from this:<p>> <i>The instant you sue Facebook, your patent rights for React — and any other Facebook ‘open source’ technology you happen to use) — are automatically revoked.</i><p>To this:<p>> <i>If you use React, you cannot go against Facebook for any patent they hold. Full period.</i><p>"Full period", really? Because the first does not imply the second. This is now how patent law works.<p>Now, I'm not a lawyer either, but broad assertions like these should tell you that there's emotion at work here, not reason. In his fourth update, he made a list of companies that add something about patents to their open source licenses, implying that somehow that that proves something.<p>So the thing that people confuse here is patents and copyrights. The BSD license grants you the right to use works copyrighted by Facebook people and contributors. The patents clause, further, promises that should Facebook hold any patents that cover the OSS, they won't use them against you, unless you sue them first.<p>There is the whole idea floating around the internet that a BSD license somehow ensures that nobody will sue you for patent infringement. I really don't understand where this comes from. Hell, Android is Apache Licensed (which includes a patent grant) and still anyone who makes an Android phone has to pay license fees to all kinds of patent trolls (Microsoft most notably). These things are totally separate.<p>So first, if you sue Facebook for patents, you lose their patent grant (so they can sue you back, which everybody always does anyway - it's the only defense companies have in patent wars). But you don't lose the BSD license or anything. That's not how it works. All you lose is Facebook's promise not to sue you because you use React.<p>Secondly, and this is the core point, patents don't cover code, they cover ideas. Any patents that Facebook might have that, right or wrong, cover React, will surely be written broad enough that they also cover Preact, Inferno, Vue.js probably, and I bet also Angular. Not using React but one of these other libraries therefore makes no difference - in both cases, Facebook can use their React-ish patents to sue you.<p>To my understanding, patent lawsuits rarely get to the nitty gritty details of actual patents in reality. It does not matter whether a Facebook patent written broadly actually covers Vue.js or not - in practice, more often than not, companies will compare the height of the patent stacks they have, and agree on a settlement based on that.<p>All this patent grant says is that Facebook gets to use their patents that cover OSS to make their stack of paper a bit higher. Like they would if they hadn't made a patent grant at all.<p>So, repeat after me: using open source does not shield you from patent infringment lawsuits.