Lower the amount of reputation needed to comment
I understand why Stack Overflow does not allow new users to comment everywhere: this keeps discussions from being dominated by "me toos!" and other potential spam left by new users who have no intention of or reason to be a respectful contributing member of the Stack Overflow community. Unfortunately, this means that many new users simply leave their comments as new answers instead, which is arguably worse because
- it takes up more screen real estate and
- it clutters up the answers section of the page rather than the comments—at least comments will auto-collapse when discussions get long!
Besides, any poor comments left by new users can be flagged for moderators' attention anyway.
Could someone explain why it is better to allow new user spam in the form of answers rather than comments?
UPDATE: My concern appears to be the same as the one voiced in this question, but as far as I can tell Jeff's answer essentially boils down to this: there are few enough new users who would provide constructive comments asking for clarification that it is disallowed.