Comment Spam PreventionComment Spam Prevention
If you enable comments on your site then you will quickly become a target of comment spammers. Below are options for dealing with comment spam.
Block IP ranges
Most spam comes from third world countries who have armies of workers posting comment spam. If your website doesn't target third world countries such as India, China, etc... then it may be in your best interest to block these visitors from your website. For example if you are a Dentist in Dallas, Texas or a Vet in Denver, Colorado then you would have no need for anyone in another country to access your website so you could contact your hosting provider and request to block users from specific countries.
Use Nofollow for Comments
The primary reason people post comment spam is to acquire links from your site. If you enable nofollow for all comment links then this will reduce comment spam from many people that specifically search for do follow comment links.
Require user registration
If you require users to register and provide a valid email address then this will significantly reduce comments. However, a lot of people do not like to register in order to post comments so if your goal is to increase the number o user comments then you may want to allow anonymous commenting. If you do then you'll definitely want to enable a spam prevention module.