Perhaps the Stack Overflow owners realize they can muscle in on the programming language documentation business. With the ongoing increase in programmers who learn a programming language at the same time as they're paid to write production code in it, the promoters of some languages will inevitably skip writing documentation that fully describes what it does and instead set up a basket of Stack Overflow users to plant lots of answered questions, which also gives the initial appearance of an existing community for that language. Eventually languages will even be designed and implemented without any thought given to documentation that explains it from beginning to end, but instead only the intention for it to be learnt in Stack Overflow-sized chunks, keyed to search engine keywords instead of documentation subheadings. And part of Stack Overflow's business model may be to host the primary documentation for these emerging types of programming languages.
Dr Dobbs magazine described this phenomenon as a "conundrum" and used Groovy as an example of this new type of language: "The endless variety of features requires considerable documentation, which is simply not available, especially for the advanced features that give Groovy much of its benefit. And so, if you jump in today, you'll find the language is easy to learn, but hard to master". http://www.drdobbs.com/jvm/the-groovy-conundrum/240147731