Commenting for new users
2514
Why do I need 50 reputation to comment? What can I do instead?
8000
How do comments work?
95252
Could new users see a notification in the space where the add comment button would be, like "you need a minimum of X reputation to comment"?
8537
Could we please be a bit nicer to new users?
105685
Use comments to ask for clarification or add more information, then what?
133971
Let's have an explicit triage system for questions from new users
59454
Use of the comment package
65040
Indicate if a new contributor is new to Stack Exchange, or new to the current Stack
81952
Blog comment moderation rules
31985
Should a user be forced to add a comment when they vote to close?
127692
One comment per user per post but be able to reply to existing comments
101134
Bonus Reputations for starters, new users
45621
How to get initial reputation on Stack Overflow with the new-user restrictions in place?
26778
Email verification for new users
9219
Add [privileges] to magic comment links
144201
Can I place  in a comment?
114694
Editing old/others' comments