There seems to be a clear effort to sidetrack many decent discussions with dumb humor

I've noticed this quite a bit in many different subs where a fairly important topic is posted and it immediately gets sidetracked with a lot of stupid comments which have the effect of totally changing the focus on the main question.

For example, someone would post (this is just an example) that the CEO killer was seen at (insert interesting / odd location here) and the OP would have a really good post about how it was strange and didn't add up.

Rather than a good discussion the top posts with many upvotes would be "he's just never been to NYC and thought he'd try a manicure before the shooting" and then 100's of comments about how he did / didn't need a manicure bla, bla, bla.

It's obviously a distraction from the original discussion and seems to be very effective in moving the spotlight from good discussions and into a stupid flood of unfunny comments.

I actually saw someone mention an actual name for this and it was something like "forum fade" or something along the lines of how forums get taken off into tangents.