Most annoying thing when running a WordPress based website is cleaning up spam comments (there is no sure why to fully eliminate it) and removing spam blogs if you run open multisite installation of WordPress. Some of the things to help with this were already part of previous articles.
If you run open blog that allows user registration and allow comments from register users only, great deal of registered users will be spam source. Eliminating such users is a big problem. Even bigger issue is multi site WordPress installation where registered users can get own blogs that can than be used as a source of spam. Filtering all that manually is very slow and tedious process. For spam comments you can use Akismet plugin and some .htaccess tricks. For spam registrations, problem is much bigger and as far as I know GD Press Tools Pro is the only plugin that can help you with that.
Best system for automatic spam comments detection and filtering is Akismet. Plugin comes built-in with every WordPress installation, and it is very easy to use and it’s usually very precise eliminating spam comments. But, it’s not perfect, especially if you run popular website that get a lot of comments each day. Here, on Dev4Press, Akismet removes some 7.000 spam comments each month, missing couple of comments each day (on average). This is really good result, and requires only minor involvement on your part. Still, I would recommend that you check comments marked as spam at least while you are sure that Akismet filter is precise and is not removing comments you might want.
Use GD Press Tools Pro to eliminate spam registrations
GD Press Tools Pro monitors all user registrations attempts and can use 9 different methods to check if the registration is valid (see image on the right). If any of the methods fail, registration will be prevented. And also, system can learn and improve filtering by using previously logged data.
Plugin will check email, username, domain part from the email and user agent from the request. Many spam registrations use invalid user agent that reveals that request is not coming from human user using browser. If any of the filtering method is triggered, it can be used to automatically ban username used, email, domain or IP. This data, if logged, it can be used further.
Plugin also has Registration panel where you can see this log, and what is banned, allowing you to manually ban or remove existing ban further improving filtering. Using this feature on several websites, I managed to prevent more than 80% of spam users registrations. With proper control of logged data, this can improve further.
Preventing spam registrations in multisite environment is very important, since spam blogs will generate content that is against the rules and topics you might allow, can cause problems with search engines, and will generate an enormous amount of warez and links and pirated content you don’t want in your network. Checking each site manually is very long and complicated process, that with GD Press Tools Pro Spam Registration prevention can be significantly faster because plugin will eliminate most of such users.