Prevent duplicate comment submissions in Drupal 7
Whenever you use a general purpose CMS and compare it to the systems built for one particular purpose, you will always miss a lot of details. This stands true when you are building an ecommerce website, a blog, a forum, and so on. However, the great thing about Drupal is that you can usually find a contrib module that provides such functionality, you can build it yourself using something like Rules or Views, or ultimately, write that in your custom module.