I'm starting to use a "movies" tag whenever I start a thread about a particular movie. btw, I'm catching Wonder Woman tonight, so I might start a thread on that one.
I figured it made sense because we have many movie-specific threads here but specific forum category for that.
"TV" or "TV shows" might be another broad tag that could be helpful, imho.
"Books" could be another if people like to discuss a specific book.
I guess the key is to suggest a tag that's broad enough that it will be applicable to a lot of new discussion threads. If it's only likely to apply to a couple of threads, it doesn't seem worth tagging.
Anyone else have any other suggested tags?