A lot of the commenting has shifted to platforms like reddit. All comments related to things posted in those forums remain there. Much easier on those platforms to keep track of comments you made, replies, etc. Most blog platforms require yet another sign-up activity. ugh... no thanks, and no I'm not going to sign in with a fb or twitter id. With all the trolls, grammar police, etc. the reward for contributing is usually just annoyance and frustration.