Archive for January, 2009

How Wikipedia enabled semantic wikis

Friday, January 16th, 2009

It turns out that yesterday was the seventh anniversary of the launch of Wikipedia, otherwise known as Wikipedia Day. So it’s probably as good a time as any to acknowledge the huge impact Wikipedia has had on my own career. It’s rare to say that a website has single-handedly brought into being an entire field of technology, but one could make a case that Wikipedia has done that for my field, semantic wikis - which is, of course, ironic, since Wikipedia itself does not use semantic technology. The site, though, has enabled what I do to come about in several different ways - enough that it’s hard to dispute the direct link. Here are the ways in which Wikipedia has made semantic wikis possible:

  • It taught the world about wikis. Most people, when they first heard about Wikipedia, a site where anyone can edit anything, probably had the same reaction: sounds like a recipe for disaster. To be sure, some critics of Wikipedia still say that’s the case; but for most of the hundreds of millions of people who read the site, seeing it work has been an eye-opening experience: the realization that a site where users can edit the content of any page can work. And for some users (including me), the realization that not only is it a workable solution, and not even just the best solution, but in some cases it’s the only solution for aggregating information in one place. And so Wikipedia’s proof-of-concept inspired many people to create their own wikis for their businesses, organizations or personal interests. I dare say that 99% of the people who have been involved with semantic wikis got their first experience with wikis by reading Wikipedia; I’m part of that group.
  • It has inspired researchers. Beyond just Wikipedia as a proof-of-concept, the idea of turning Wikipedia into more a database-like information store has captured the imaginations of a lot of people. That’s how Semantic MediaWiki got its start: the first paper published about the project was titled “Semantic Wikipedia”, and the concept remains the holy grail for many of those involed with the project (not for me personally, though I can understand the excitement). And Freebase, the other major semantic wiki technology (in my opinion), which uses its own proprietary application, has billed itself as a “Wikipedia for data”; I wouldn’t be surprised if it was conceived that way too. (It’s an open question what will happen to Freebase if Wikipedia goes semantic, and thus itself becomes the Wikipedia for data.)
  • It has enabled the technology. MediaWiki, the wiki engine developed specifically for Wikipedia, is also, in my opinion, the best wiki engine, of the dozens that exist. It’s robust, scalable, and full of useful features. Two of those features have, I think, made it ideally suited for use in semantic wikis: templates and hooks. Templates enable the separation of data from data structure and presentation, which lets a semantic wiki approximate much more closely a regular database-driven website; while hooks, of which MediaWiki has hundreds, allow extensions like Semantic MediaWiki to integrate nicely into the rest of the package with little or no coordination between the extension developers and the main MediaWiki developers: that, in turn, allows for much faster development time. Neither one is a coincidence: the nature of Wikipedia and its massive size make conveniences like these into something more like necessities.

So, a big thank you to Wikipedia, and of course to its two co-founders: Larry Sanger, who had the idea to use a wiki to power the world’s first free online encyclopedia; and Jimmy Wales, who has guided the project successfully through ever since.

New MediaWiki extension: External Data

Tuesday, January 13th, 2009

I’m pleased to announce External Data, my new MediaWiki extension; this is somewhere between my sixth and ninth released extension, depending on how you count it. External Data allows wiki pages to use and display values that were retrieved from an outside URL that itself holds XML or CSV data. It’s a very simple extension (my smallest one, I think), but I think it has some important implications for SMW. Using it, one Semantic MediaWiki-based site can get the data from another, using a query with the ‘CSV’ format, and then store it semantically. See here for an example of that usage, on Discourse DB - it displays and then semantically stores data that was retrieved from this page on Check out the source code of the first page for the specifics of how it’s done. This means that now the information from two or more semantic wikis can be combined together in one place, then queried, mapped, etc., as if it were all just one wiki’s data.

This idea of pooling data from different websites is of course the main concept behind the so-called Semantic Web (not a term I like all that much, but that’s a different story). At the moment, I can’t imagine that this extension will be used much for the classic semantic-web example, of gathering data from completely unrelated wikis (or what could be called a “mashup”); but for wikis and other online data sources that have already coordinated among themselves to split up the handling of data, I think it’s a very reasonable solution for doing that.

New Semantic MediaWiki hosting site

Monday, January 5th, 2009

The site Pseudomenon, which appears to have just been released yesterday, is the newest entrant to the small club of semantic wiki hosting sites. This is, as far as I know, the third site to offer hosting of Semantic MediaWiki, and the fourth to offer hosting of any sort of semantic wiki, the one non-SMW site being Swirrl. It’s the first, though, to support the Halo extension (also known as “SMW+”), which allows free-form semantic annotation and querying of wiki pages. Pseudomenon doesn’t include any other extensions at the moment, but the inclusion of Halo by itself makes it a helpful addition.

According to the main page, hosting is free, and every wiki gets a subdomain at

Apparently, the word “pseudomenon” is a reference to the Epimenides paradox, in which a Cretan stated “all Cretans are liars”. A snide commentary on truth in wikis? Well, at least it’s a real word, as opposed to the fake-Latin “Referata” I came up with, though I later found out that means, I believe, “reports” in Croatian.