The AbuseFilter extension, developed by User:Werdna, is now enabled on English Wikipedia. The extension allows all edits to be checked against automatic filters and heuristics, which can be set up to look for patterns of vandalism including page move vandalism and juvenile-type vandalism, as well as common newbie mistakes. When a match is found, the extension can take specified actions, ranging from logging the edit to be checked, giving a warning (e.g. "did you really intend to blank a page?"), to more serious actions such as blocking users.
With the warnings, the user sees a message before the edit is saved. After seeing a warning, the user can click Save page again to proceed with the edit. Such warnings, however, have the potential to stop a substantial portion of unconstructive edits before they are saved. In the first five days of using the extension (March 18 - 22), warnings for page blankings were given to 1,926 individual new users and IPs. Of these, 1,391 (72.2%) did not save the page after being warned, while 464 (24.1%) of these users went on to save the page, with the page blanking, and 71 (3.7%) saved multiple page blankings despite receiving multiple warnings.
The more serious actions, such as blocking users, are not yet enabled, giving time for admins to become familiar with the new extension and how to create, test, and optimize filters. Time is also needed for the developers to evaluate performance of the filters, as currently used.
Soon after the extension was enabled, developers had to temporarily disable it for a few minutes due to performance problems when edits were being saved. Some filters were placing a much heavier load on the servers. The problematic filters were removed, and Werdna added a profiler tool that can be used to test filters before implementing them. Errors made by administrators also resulted in a filter that was triggered on all edits, and deautoconfirmed 200 users before the filter was disabled. The users affected were reautoconfirmed using the extension's "mass revert" feature.
The ability to add and manage filters is currently restricted to the "Abuse Filter editor" user group, with admins able to place themselves into that user group. Developers are urging abuse filter editors to very carefully test filters and proceed with great caution. There is ongoing discussion on whether or not (and how) the "abuse filter editor" right should be given out to non-admins, similar to the rollbacker and account creation rights, recognizing that some non-admins may have a high level of technical competence and ability for managing filters. On the other hand, there is concern for misuse of the abuse filter.
Sample Abuse Filter warning
Warning: An automated filter has identified this edit as potentially unconstructive. Please do not replace Wikipedia pages with blank content. Blank pages are harmful to Wikipedia because they have a tendency to confuse readers.
If it is a duplicate article, please redirect it to an appropriate existing page.
If the page has been vandalised, please revert it to the last legitimate version.
If you feel that the content of a page is inappropriate, please edit the page and replace it with appropriate content or leave a message on the talk page.
If you believe the page should be deleted altogether, please see the deletion policy for information on how to proceed.
If this edit is constructive, please click 'Publish changes' again, and report this error.