Over time, a large number of extensions (over 1500) have been written for the MediaWiki software on which Wikimedia wikis and other sites are based. A small percentage of these (approximately 80, in fact) are enabled on Wikimedia wikis. Today's What is? section looks at Semantic MediaWiki (official site), a package of extensions that are not currently enabled on Wikimedia wikis.
What are the hundred world-largest cities with a female mayor? Wikipedia should be able to provide the answer: it contains all large cities, their mayors, and articles about the mayor that tell us about their gender. Yet the question is almost impossible to answer for a human, since one would have to read all articles about all large cities first! ... Computers can deal with large datasets much easier, yet they are not able to support us very much when seeking answers from a wiki: even sophisticated programs cannot yet read and understand human-language texts unless the topic and language of the text is very restricted [which is not the case on Wikipedia].
Semantic MediaWiki (shortened to SMW) allows those writing an article to use tags like "[[Has population::82,060,000]]" to allow automated tools to understand the answers to these sort of questions. In practical terms, many such tags would be included in infoboxes. Once it's there, a new breed of maps, calendars and graphs can be generated from it, and the data can also be passed on to third party users easily and in a machine-readable format.
Several hundred wikis do use the software, however, and there have long been calls to deploy it to at least some of the Foundation's wikis. Several SMW developers were invited to give presentations at the WMF's "Data Summit" in February (Signpost coverage). Though developers at the WMF are not yet satisfied that SMW can scale to meet the demands of the many millions of users Wikipedia and other WMF wikis get (Deputy Director Erik Möller recently called it "still a big heap of 'untrusted code' ... that we're not prepared to host on our main cluster yet"), many will undoubtedly be interested to see how SMW adoption progresses over time.
Not all fixes may have gone live to WMF sites at the time of writing; some may not be scheduled to go live for many weeks.
Wikimedia sites experienced an unusually high level of server errors from April 19 onwards which system administrator Ryan Lane blamed on "upgrading too many" Squid caching servers at the same time (wikitech-l mailing list). As a result, several servers were temporarily downgraded again (server admin log).
The addition of new sections to a page can no longer be marked as a "Minor" edit (bug #27860).
As of 19 April a new developer, Patrick Reilly, has been hired to rewrite the mobile site, m.wikipedia.org. The fundamental problems with the site were highlighted in a post this week to the wikitech-l mailing list.
Including a non-existent file will now trigger addition to a tracking category, in a similar way to existing cite-errors (bug #23816).
Wikis can enable account resetting by entering solely an email address in the event of a user forgetting their username, though a decision has not been taken on whether this will be enabled on WMF wikis due to performance concerns (bug #13015). In addition, for all wikis, registered users' IP addresses will not be sent in the password reset emails (bug #18347).