It is based on the WMF-developed ArticleFeedback MediaWiki extension and currently deployed on a subset of pages on the English Wikipedia.
A new version 5 of the Article Feedback Tool is under development, with a new emphasis on engaging readers to participate more on Wikipedia.
See also the Frequently asked questions.
Project update 
Here's our latest update on Article Feedback:
Project history 
- A detailed log of Article Feedback milestones and releases is also available.
Version 1: Public policy pilot 
The Wikimedia Foundation has been experimenting with a feature to capture reader quality assessments of articles since September 2010.
The feature was originally designed to support the Public Policy Initiative, as part of the Public policy pilot. This version was deployed in September 2010 on the English Wikipedia (see announcement).
Documents for version 1:
Version 2 
Version 2 featured a modified design, including a checkbox that could be used by the rater to self-assess their expertise.
Calls to action were also added, to invite the rater, after the completion of the rating process, to take an additional action: creating an account, taking a survey, or editing the page.
In March 2011, version 2.0 was enabled on approximately 3,000 additional articles of the English Wikipedia (see announcement).
Documents for version 2:
Version 3 
Version 3 featured an e-mail option to test systematic e-mail calls-to-action targeting self-identified expert raters. The expertise self-assessment checkbox started to be A/B tested. It was released to the ~3,000 articles already in the experiment on the English Wikipedia on April 28, 2011.
Given the encouraging results of the trial until then, the feature's use was expanded to approximately 100,000 articles of the English Wikipedia in the week of May 9, 2011. Articles were selected at random (versus the stratified-random sampling used for the 3,000 articles). The primary goal of this roll-out was to test the scalability of the feature.
A ratings dashboard was also added, in order to surface articles to the editing community that were being rated very highly or very lowly.
Version 4 
On May 26, 2011, the expertise self-assessment checkbox was restored for all users. A "What's this?" link was added on June 3 per popular request.
Version 4 also features a user preference to hide the article feedback interface, enabled on June 10, 2011.
On June 30, 2011, explanatory tooltips were added for each rating (i.e., "What does one star mean?"), instead of a unique tooltip for the criterion.
AFTv4 was deployed to the entire English Wikipedia in July 2012.
Version 5 
In October 2011, we officially kicked off the product development process on new and alternative methods of providing feedback regarding the quality of articles, including ideas like a moderated free-text comment queue for suggestions. (Version 5). For that purpose, the Foundation hired Fabrice Florin as product manager for new editor engagement. The goals for this new tool were to: 1) provide lightweight contribution mechanisms as a gateway to editing; and 2) provide meaningful feedback regarding the development of articles to the editing community.
Enabling Article Feedback on Pages you Watch 
English Wikipedia editors who wish to enable AFT5 on articles they watch can simply add this special 'Category:Article_Feedback_5' to these articles -- and the feedback form will automatically appear at the bottom of these pages. Editors who add AFT5 are encouraged to moderate feedback periodically for those articles (using the reader feedback link at the top of their article talk pages).
Hiding Tool from View 
Users that do not wish to see the Article Feedback Tool may hide it from their view by going to My Preferences --> Appearance --> and checking the "Don't show the Article feedback widget on pages" box.
Current status 
Version 4 of the feature is currently in use on all articles of the English Wikipedia.
Version 5 is now under development, as described above.
Quantitative research 
As of AFT v5, all research reports are hosted on Meta.
We're still learning from the feature, and based on the work so far, we think that Article feedback has a lot of potential:
- Quality assessment: article feedback can help complement internal quality assessment of Wikipedia articles with a new source of data on quality, surfacing content of potentially very high or very low quality, and measuring change over time.
- Reader engagement:article feedback represents a way to encourage participation from the reader community.
- Quantitative Research reports
- Version 1 feedback survey text
- Version 2 feedback survey text
- Call to action
- Rater expertise
- Post-rating survey
User experience research 
Initial UX research 
Usability testing 
Usability testing videos from May 2011:
As we are still learning about the use of this feature, no decisions on future enhancements have been made. A log of feature requests and possible improvements is being maintained.
In the longer term, we hope to be able to explore some more complex ideas, including:
- enabling readers to leave free-text comments specifying issues with the article
- enabling readers to praise the authors of an article, and enabling authors to receive praise
- enabling editors to collaboratively filter rater comments and issue reports, and to promote comments of special significance to the talk page
- enabling raters to attach credentials to a Wikipedia user account, which will then be associated with their rating.
- improving the user interface integration of the tool to reduce initial screen real estate usage while increasing visibility/discoverability.
These ideas are described in more detail on the extended review proposal, a possible evolution of the feature to conduct open peer quality review.
Other documents 
- Frequently asked questions
- Call to action review & discussion
- Article feedback on Wikimedia Commons.