People can prohibit others from using their ideas. This protection is called "patent".
Facebooks license grants you usage rights of their patented ideas with the tiny caveat that they take this grant away if you sue them when they use your patented ideas.
This can be bad. For example when Facebook want to use your patented ideas to harm you and you use their ideas. Now you would have to get rid of all patented Facebook ideas in your codebase.
But the root of the problem isn't the license but the patents, because Facebook has many of them. In fact, so many, that potentially all non-trivial software uses patented facebook ideas.
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We're a place where coders share, stay up-to-date and grow their careers.
People can prohibit others from using their ideas. This protection is called "patent".
Facebooks license grants you usage rights of their patented ideas with the tiny caveat that they take this grant away if you sue them when they use your patented ideas.
This can be bad. For example when Facebook want to use your patented ideas to harm you and you use their ideas. Now you would have to get rid of all patented Facebook ideas in your codebase.
But the root of the problem isn't the license but the patents, because Facebook has many of them. In fact, so many, that potentially all non-trivial software uses patented facebook ideas.