Possible Duplicate:
How do comments work?
How do you post a comment to a question or answer. The FAQs suggests 'comments' as a possibility, https://stackoverflow.com/faq#howtoask but there isn't a comments link next to edit or similar.
How do people do it?
You need enough reputation to post comments on questions or answers that are not your own.
The threshold is 50 reputation, as you can see in the privileges page. You currently have 21 reputation on Stack Overflow, so 30 more before you can comment on any post.
Also see How do comments work? (community FAQ).
