Allow comments for all users; create comments review queue
44432
Allow anyone to comment but hide low-rep users' comments until reviewed
66878
Taking ownership of comments on migrated questions
129908
Allow flagging own comments
61716
For protected questions, require local reputation to comment
9219
Add [privileges] to magic comment links
1334
Adding a comment should not make me fail the review audit
133230
Why is deleting comments allowed?
15279
Implement a Selective Comment Ban
56841
Make it more obvious that commenting is only possible after earning certain reputation
110606
Can we get a comments only lock?
117715
Always allow commenting on posts I have previously commented, irrespective of current rep
50676
Is everyone in favor of the new "everyone can edit" idea? Is this really such a good idea?
18197
Allow mods to edit revision comments
148524
Why does Stack Overflow prevent new users from commenting?
105735
Flag individual comments or flag once for many?
82959
Can we have threaded comments?
97524
Allow bounty owners to comment on questions they've placed a bounty on, even if they have less than 50 reputation