I run a small forum, and it was getting flooded with fake and spam accounts, the moderators were struggling to keep up and the users were finding it annoying. S

I run a small forum, and it was getting flooded with fake and spam accounts, the moderators were struggling to keep up and the users were finding it annoying. So I put a captcha on the registration page. The problem went to zero, new users still showed up, and more people were happier than before.