Many users of these platforms, blatantly plagiarize ideas or Original work without giving due credit to source.

Example https://www.quora.com/What-are-some-psychological-tricks-that-everyone-should-know/answer/Nikunj-Kothari-1

It was copied from

http://www.esquire.co.uk/culture/article/6300/14-simple-bits-of-psychology-everyone-should-know/

But there was no source link given in the answer, after repeated suggestion user finally added source link. This is just one example. There are many such answers, where users use stories/articles written by others as their own.