As discussed in this thread, MC's Automatic Medatada Lookup system is currently mapping TMDb's Plot Keywords "field" to MC's [Keywords] field. This is useless because those Plot Keywords on TMDb's site really seem to be designed to be "search hints" for TMDb's Search Engine.
So, if you use MC's built-in lookup system currently, your [Keywords] field for movies very quickly becomes filled with all sorts of awesome things like "on the run", "cemetery", "bravery", and "snake" for
Harry Potter and the Deathly Hallows, Part 1 (as an example). The Plot Keywords are junk, and most users (who commented in the above-referenced thread) agree.
Proposed Solution: Map TMDb's Genres field to [Keywords] instead.
TMDb has nice information in the Genres field. You can't map this directly to MC's [Genre] field though because the TMDb version is a list-type field, and MC's [Genre] field is a string-type field.
There are two upsides to switching this:
1. [Keywords] is used in the default Video views in both Theater View and Standard View. Therefore, it will be very painless to existing users to make use of this new automatically-obtained data without having to reset their views or build a new view from scratch.
2. TMDb's Plot Keywords are bad, and they are already filling our [Keywords] field up with junk. Any user who is already using the [Keywords] field to store Genre information is a LOT more likely to be happy with the contents of TMDb's Genre field rather than the Plot Keywords field (that I can't imagine anyone wants). If they aren't, then they can move their existing data to a new custom field before they enable the Metadata lookup.
The downside is that anyone who has been using the Plot Keywords form TMDb on purpose would be unable to continue doing so. But, is there anyone actually in this camp? The other downside is that the name [Keywords] does not necessarily "intuitively map" to TMDb's use of "genre" to describe the contents of the field.
Alternate Solution: Create a [Movie Genre] default field in MC (list-type) and map TMDb's Genre information to this field (and leave the existing mapping alone).
This has the upside of not messing with an existing system, and the Field Naming is more reasonable. However, it has a potentially big downside:
You will have to create new default views that include this new [Movie Genre] field for it to be useful (it will need to be turned on in the Video views' columns by default, and it will need to be used as a category in Standard, Theater, and Media Network views. This isn't a big deal for new users, but most existing users will never notice that it is there. Existing users will have to reset all of their views back to the default, or manually modify their relevant views, to even KNOW that MC is filling this new tag with information and be able to use it.
Either of these two solutions would work for me, and would, I believe, work for the other people commenting in the above-referenced thread. So, which of these two options you choose is your call.
In any case, the current behavior of mapping TMDb's Plot Keywords field to [Keywords] is useless.