I just ran across a couple of questions relating to the need for 50 reputation points before commenting on other people's questions, such as Lower the amount of reputation needed to comment
The limit is to prevent low-quality comments from cluttering the site. My question is, was this assumption tested? Were comments originally unrestricted when they were introduced? Was there any experimentation on the value of the threshold?
My own personal opinion is that the threshold does more harm than good by driving away people that would become engaged in the site, but I'd love to be proven wrong.
OK, I concede that preventing the spambots from overrunning the site required some sort of threshold on day 1. I also concede that without a way of measuring good comments vs. bad that there's no good way to test a different threshold. Since nobody has put forth an observation that the limit has been any different value, I'll conclude that it has always been 50.
I'll persist in my opinion that the threshold is set too high, misguided it may be.