so for some reason this feature was actually announced on the tumblr engineering blog. interesting choice not to reblog it to the staff or tumblr blog, esp considering they asked for user input on how to implement it, but i suppose considering the response to the last update maybe the replies would be too overwhelming...
posts you comment on may show on your followers 'for you' page if you leave your replies publically available. they may, in the future, show in on your followers dashboard if your follower goes to their dash settings and enables this. apparently, if your likes are enabled, your followers can already see those on the dash if they've gone into preferences and selected to do so, which I was unaware of, and that seems to be disabled at default, but it's possible i disabled it previously and forgot about it ig