Forum Spam: What You Can Do Against Unwanted Advertising in Your Forum

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Almost every forum owner has had an unpleasant experience with spam in his forum. The most common type is the so-called SEO spam. In this case, the spammer posts a text with links with the intention of getting a higher ranking for the linked website in search engines. Over the years, a whole industry of companies has emerged that offers or mediates such spreading of forum spam.

A common misconception is that spam always comes from so-called spam robots. In fact, spam in forums often comes from human spammers.

Spam robots are usually simple software programs that spread spam in a fully automated way, but can also be easily blocked out by technical measures because they are rigid in their behavior. Human spammers, on the other hand, are a much bigger problem, as they can easily circumvent technical measures designed to exclude robots.

Create a Forum with WoltLab Suite

In the following, we will show you how to make life difficult for both spam robots and human spammers. The measures shown are based on the functionality of the current version of our forum software WoltLab Suite.

This indicates to search engines that they should not follow the links in the forum posts and thus makes posting SEO spam much less attractive for the spammer. In our forum software WoltLab Suite, the links are already configured this way by default. Especially the newer attribute "ugc" is recommended by search engines such as Google to specifically mark links that come from "user generated content", i.e. from third parties.

Activate a Captcha in the Registration Form

Captchas primarily help against spam robots. An alternative to reCAPTCHA is the use of a question&answer captcha. Define different questions from which a user has to answer a random one during registration. Tip: Test your questions beforehand as a search term on Google. If the search engine spits out the right answer directly (as in the case of simple arithmetic problems, for example), a question is too easy and can also be easily solved by spam robots.

Use Stop Forum Spam

The creation of user accounts and associated e-mail addresses is a real obstacle for spammers in the masses, which is why the same information, especially e-mail addresses, are reused on many sites. The "Stop Forum Spam" project aims to collect the data of spammers and make it available via a central database. The chances are therefore good that the registration details of a spammer is already preloaded and spammers can thus be reliably detected before they are able to write their first words.

The WoltLab Suite offers you a default integration with Stop Forum Spam to detect suspicious cases during the registration process and requiring these users to be manually approved by the administrator. In order to comply with the strict requirements of the GDPR, the check is done by means of a local copy of the database; no personal data is ever transmitted to third parties.

Ask for Confirmation of the Email Address

Configure your forum so that the user has to confirm his email address after registration and that he is not allowed to write posts or other content until then. Also the editing of the user profile should be restricted if necessary, as this is also often used for SEO spam (e.g. in the "about me" text).

Restrict the Editing Capabilities

Spammers like to use the trick of writing posts with harmless content at first and only later inserting the spam by editing, often days or even weeks later. Therefore, it may be advisable to limit the time for editing posts to a few minutes, at least for new users.

Manually Enable New Users

Especially for smaller communities, it can be useful to manually check each new registration as an administrator and only approve the user account after a successful check.

Activate Flood Control

The flood control ensures that a user can only post a limited number of posts within a certain period of time. Especially for new users this restriction is recommended, because it prevents a spammer from creating countless spam posts in your forum within a short period of time.

Manually Review and Approve Content from New Users

If there is a severe problem with spam, it may be advisable to approve content from new users only after manual review. This is time-consuming, but usually ensures that spammers quickly find another website for their spam. Tip: Use automatic group assignment to automatically assign users who have passed the "probationary period" to a user group that can post content without prior review.


Note that every measure against spammers can be unpleasant for legitimate users at the same time. Therefore, measures should always be selected on an as-needed basis and new measures should be activated only gradually, so that it is possible to evaluate whether a single measure has worked at all. Forum spam has very different sources and also changes regularly, so not every measure will prove to be effective all the time.

As a forum admin, what experience have you had with forum spam? How else can forum spam be effectively combated? Share it with us in the comments!