Why does Stack Overflow prevent new users from commenting? [duplicate]

Question

Recently, I was told:

Welcome to Stack Overflow. You'll get the privilege to add comments when you get 50 reputation points. Until then, don't post comments as answers.

That "answer" got converted into a comment (by the responder or some automated process). I wanted to make a simple comment in the first place anyway.

Since comments are often less obtrusive than answers (and can sometimes be much more pertinent, like when pointing out errors in code or grammar or orthograph), why are new users allowed to answer but not to comment? What is the reasoning behind this bizarre restriction?

Answer 1

There are three reasons.

The first reason is instructional.

There is a tendency among new users to treat Stack Overflow as if it were just another forum. However, the Q&A format here and the expectations surrounding it have some fundamental differences from forums. In that context, there is a tendency to (ab)use the comments feature for extended discussion, something Stack Overflow tries to discourage. The purpose, then, in limiting comments is to first give a new user time to understand how the site is different and what the expectations are for their commenting behavior.

The second reason is moderation

Site users can self-moderate a lot of what is done in questions and answers. They cannot as easily self moderate comments. That requires bringing in a designated mod (though flags), and on a site the size of Stack Overflow this doesn't scale well. Since new users are less trusted, we need to make sure they are contributing at first in ways that can be more easily moderated by high-rep users vs diamond-mods.

The third reason is to reduce abuse.

Note that you can always comment on your own answers, your own questions, and any answers to your own questions. Comments are also voted on differently than questions and answers, and don't affect your reputation.

With that in mind, comments could provide an easy avenue for abusive behavior among users. Someone does something you don't like? Just fake a new account and abuse them with comments from it. Your reputation score is immune, and your name isn't attached, so it's (nearly) consequence free. Limiting comments makes this harder, and means that you have at least one account that you're likely to care about (even if just a little bit), in case mods need to suspend you for bad behavior.

Answer 2

Answers are the raison d'être of Stack Overflow. Not comments.

When people first come to the site, this is what we want to teach them first: how to post good answers. We requires 50 reputation to post comments on other people's posts. By that time, it is assumed that you have gained some familiarity with the system and its etiquette.

Forcing new users to post answers instead of comments causes spammy answers and non-answers to surface very quickly and prominently, so that they can be removed. Answers so removed have a system link that points to the FAQ and other resources, explaining how the system works. These answers are subject to the same system quality checks that everyone else is bound by (answer bans, and so forth).

Comments do not have these system checks and resources, and are largely an unregulated system for the most part, so we require people to gain some system trust before we let people use them.