It makes the library unusable for anyone, but open source software.<p>If you write any sort of software, and link against this library, boom all the code needs to be GPL&#x27;ed.<p>I don&#x27;t think that&#x27;s a good thing for promoting a library&#x27;s use. Most people will just not use the library, and leave a bad taste in there mouth rather than spread the use of GPL.<p>If you want your library to popular don&#x27;t use GPL.<p>What happens is that someone else comes a long and creates a MIT version. Eventually it gets replaced with the MIT version.