Possible Duplicate:
How do comments work?
I mean, comment on a comment? How do I do that?
You need 50 rep to comment globally, unless it's either …
your question
an answer to your question
… in which case you can comment with 1 rep.
Meta has a different ruleset from the other trilogy sites and allows global commenting with 1 rep. All rep levels are documented on the /faq page as usual.
(shamelessly stolen from mmeyers' comment, but he should have left it as an answer!)
You have to have 50 reputation before you can leave a comment on stackoverflow, but you only need 1 on meta.
I understand that you mean : To comment not on a question or answer, but on one of theirs comments.
What I've seen, and am doing also, is to prefix my answer with @author
, where author
is the name of the person who wrote the comment.