This is not directed at anyone specifically, the moderators have just noted an increase in the number of incidences of this from a number of contributors. Everyone's contribution here is incredibly valuable, and this is done for well intentioned purposes, so please do not take this the wrong way.
There are a number of websites on the internet, such as Wikipedia and IMDB that people use to look up information about Movies and TV shows. When using content from many sites, please be aware that they are usually covered by Copyright Law, and each site probably has a specific usage policy. There are 'fair use' aspects to copyright law, but for instance Wikipedia specifically places conditions of acknowledging the source of the material:
This is easy to do in a Question or Answer, by acknowledging wikipedia as the source, and preferably having a link back to the article concerned. This actually adds to the post here, as it allows users to more quickly read more, so I would encourage that.
However it is harder for Tag Wiki elements - and this is where we see the most use of unattributed copyrighted material. Please try to not just copy material for these, but to write the content in your own words. If you are reviewing Tag Wiki material and think it might be copied, quickly check it out (by searching for the text - usually finds the source very quickly), and reject the edit using the 'copied material' reason.