A few updates ago, Plex switched to a a new database for movie genres. According to what I can find from a cursory scan, it is Freebase). Previously it used IMDb, which only had a very limited set of genres. So it was supposed to be an improvement. However, when I browse through movies in Plex I now see things like this:
If someone would pick REC or The Fly for a romantic evening with their girlfriend, things would not end well. And in what way is “black-and-white” a genre? And don't get me started about “airplanes and airports”. Apparently I misunderstood the whole point of Indiana Jones. They should have made it more obvious that it was all about Indy hopping from one airport terminal to another.
When browsing through the films in Plex Media Manager, they prove to have multiple genres and the second genre often makes a lot more sense than the first (e.g. Thriller for Sin City, Horror for REC).
I can guess how this database came into existence even by only taking a glance at the Google results page for the “freebase” thing I did not know until now. It probably works in a similar way as the good old Google Image labeler, where random people are encouraged to slap as many labels onto random images as possible. The people who have the most time for doing this are children and teenagers, whose first impression of a film like Sin City is “it's black-and-white!” (Which is wrong by the way, there is quite a bit of colour in it.) Therefore the labels that get the most weight, are the ones that these age groups consider relevant. Maybe it would be helpful if the database would keep track of what labels were assigned by what age groups. Any user of the database could then re-weight the entries according to an age group of interest.