I haven’t seen any, but the people that would have access to that data are probably too busy to care. For example, Political Wire noticed a significant decrease in the right-wing trolls, with one longtime nuisance disappearing completely and the general discussion just being way less divisive. The site is basically run by one guy, and he doesn’t have the time or expertise to do some sort of analysis on this. Also, we aren’t talking about some huge number of people here. It only takes a couple of trolls to ruin an online forum, so if the strikes knocked out only a couple dozen trolls, it could make a noticeable difference in the online discourse while being virtually unnoticeable in the overall data.