I don't mean setting a rating limit like only pupil or higher people can post a blog or send talk . That's discrimination. But asking who writes comments to participate in at least one Codeforces contest is proper , even they get WA on A and don't pass any problem. I'm just sad to see many spams or disrespectful comments due to many causes. People want to make spoofs but don't want to get downvoted, so they create another account. Most of them are children under 14. I hope this can help to increase the time cost of it. No kid would create an account ,wait for another contest, just to look funny in public , I think.