Admin:Link Spam

We have had a significant problem with Link Spam on this wiki in recent months (late 2011). We do not wish to prevent public contributions altogether, as any corrections to the Symbian OS Platform Security book are still very welcome and some new material is about to be added to the site which we hope will promote some public participation.

A while back we disabled anonymous article creation and added a CAPTCHA to anonymous article edits, but that hasn't reduced the quantity of spam; it has continued to increase until we're deleting spam articles on an almost daily basis. We are now taking the following steps:

Disabling indexing and ranking of link spam

On the basis that the motivation for link spam is to increase the PageRank™ of the spammers' sites, we aim to make that ineffective by ensuring that the edits are not indexed by Google. We have disabled indexing of all pages in the "Special:" name space, which includes the change history, using a site robots policy. External links from this wiki are ignored for ranking due to the inclusion of the nofollow attribute. Indexing of deleted content from page histories is disabled using the robots meta tag with noindex and nofollow.

Blocking references to known spam sites

We have installed the SpamBlacklist MediaWiki extension. This uses an actively maintained blacklist to block edits containing URLs of sites included in spammed content.

Looking for patterns in IP addresses used

We have installed the CheckUser MediaWiki extension. This allows us to see the IP addresses used for page edits from logged-in users as well as anonymous users. We intend to block IP addresses that are the source of repeated spam for much longer than the default autoblock period of 1 day.

The above measures have sadly not stemmed the rising tide of spam; we have now also disabled anonymous article edits, and new user accounts will require confirmation from an administrator.