New users should be able to comment in order to contribute
44432
Allow anyone to comment but hide low-rep users' comments until reviewed
68981
Improve the usability/intuitiveness of direct comment links
51469
Allow converting comments to answers
59454
Use of the comment package
101134
Bonus Reputations for starters, new users
65040
Indicate if a new contributor is new to Stack Exchange, or new to the current Stack
9269
Let's make it easier to reply within comments!
41334
Please make pending edit suggesters be @reply-able in comments
77934
Why there isn't a feature that lets any user on SO to request other user to answer their question?
51535
What's the justification for the commenting reputation requirement?
87776
Allow voting on comments from Review interface
5021
When to comment or answer
101219
Allow comments for all users; create comments review queue
130885
Information of the user in comments
61817
Comment first, then answer, what's the etiquette?
23912
Add a confirmation before moving comments to a chat
135342
Warn new users to edit important information into the question upon their first attempt to comment on a question of theirs