Response to dang: I disagree with the no-delete policy (our comments are ours and we should have the ability to delete them), but more importantly I refuse to leave a comment up when my ability to reply has been disabled.
I strongly disagree with this. When you're part of a conversation your comments are critical to understanding the conversation. By having a conversation in a public space, you're allowing anyone who wants to listen in, and your comments are necessary for that. I can't tell you how frustrated I've been searching through old reddit threads in particular where the user has completely nuked their account, and the only trace of what they said is in replies. (Worst is when it's a technical issue and their comments are the only relevant search results: xkcd.com/979 where the answer has been actively removed.)
If you want to have a private conversation, please use a private medium. Otherwise you're gaining the benefit of public spaces (you can view anyone's conversation, their ideas and wisdom, and watch the development of discussions and understanding) while preventing others from gaining those same benefits.
[1] subject to obvious exceptions like accidentally revealing personal/private information, it being spam/off-topic, or a misunderstanding (editing with a correction is my preference though)
How was it before? It would be constructive if you could point out some differences. I understand that they can be subtle and hard to discern but I would appreciate any pointers to satiate my curiosity.