Highlight answerer's name in comments
48650
Highlight comments from answer author, in addition to question author
144201
Can I place  in a comment?
26712
How about newlines within comments?
30544
Bold code in a question
124089
Commenting out a few words within a paragraph?
76476
Change all @username references in comments when a user changes their name?
113721
Why comment reply auto-completion feature (@) sometimes doesn't work?
98110
Show if/when the answer was seen by the author of the question
153278
Please show reputation when hovering over a user name in the flag queue (or flag view on a post) like you do for comments
97892
See question when answering
114749
Allow post editor to see @comments directed at him
19115
Mark a comment as the answer to a question
119727
Notify users when they are mentioned (on meta)
128221
Promoting comments to answers
128064
Is the @reply in a comment to the editor of a post broken?
23614
A method for the OP to accept comments?
91466
Mark answer as favorite/star