Given a collection of archived web pages, known as mementos, the Off Topic Memento Toolkit (OTMT) allows one to determine which mementos are off-topic. Mementos are produced by crawling live web pages, resulting in collections that often contain different versions of the same web page. In time, due to hacking, loss of ownership of the domain, or even website restructuring, a web page can go off-topic, resulting in the collection containing off-topic mementos. The OTMT helps users detect these off-topic mementos before conducting research on their collections of archived web pages.
The idea of the Memento extension is it to make it as straightforward to access articles of the past as it is to access their current version. The Memento framework allows you to see versions of articles as they existed at some date in the past. All you need to do is enter a URL of an article in your browser and specify the desired date in a browser plug-in. This way you can browse the Web of the past. What the Memento extension will present to you is a version of the article as it existed on or very close to the selected date. Obviously, this will only work if previous (archived) versions are available on the Web. Fortunately, MediaWiki is a Content Management System which implies that it maintains all revisions made to an article. This extension leverages this archiving functionality and provides native Memento support for MediaWiki.