Wikipedia:Administrators' guide/Dealing with spam

On the world's largest encyclopedia that anyone can edit, and where it's content has a powerful search engine presence, spam is an inevitable and ongoing problem. Fortunately admins have numerous tools to fight it.

First steps

The first attempts to prevent the spam follows how you would deal with any abuse. In ascending order of the things you should try:

Block the spammers, provided the disruption is limited to one or a few users, and they've received sufficient warning. For a spam only account, you can block indefinitely and template them using {{uw-soablock}}. If they are also editing under a promotional username you can instead use {{uw-spamublock}}. In the case of the latter, you may not need to issue all four levels of warnings before blocking. However be sure to not to confuse obvious spam-only accounts with those who have good intentions, in which case you could perform a soft block and issue the {{uw-softerblock}} template.
Protect the affected pages. Oftentimes multiple IPs will add promotional content to a page for which they have a conflict of interest. Here instead of making multiple blocks on what could be shared IPs, simply semi-protect the page. Use the same procedure as protecting against any abuse: start with a short duration and extend it as necessary.
User:XLinkBot – A nifty bot that patrols recent changes and reverts edits containing certain external links. The configuration for this bot can get quite complex, but in it's simplest form you can add the link to the revert list using regular expressions. This does not prevent reference spamming, and limits it to a single revert. To ensure the bot always reverts a link addition you can also add the regex to override list or hard override list, but this should only be used for short-term issues. Beyond the simple revert lists, you can instruct the bot to only revert on certain pages, or from certain users, and even have it issue customized warnings. See the bot's user page for the full instructions. Please read the instructions and ensure you know what you are doing. Seek help from other admins at WP:AN if you are unsure.