Semantic MediaWiki is a semantic extension to MediaWiki, the wiki platform on which Wikipedia is built. MediaWiki itself is serious business: It is used by thousands of organizations as the base for their websites and Wikipedia is the sixth most active website in the world. MediaWiki can be scaled to accept thousands of editions and millions of visits per hours. There is no doubt MediaWiki is an incredibly robust website development platform.
Semantic MediaWiki (SMW) adds the possibility to add structured data to MediaWiki pages. In other terms: "to create objects (pages) of a certain class (category) having certain properties". For those with a relational database background the transcription looks like: "to create records in tables having certain attributes". With the SMW extension (and a bunch of other extensions), you can build a complete relational database on the web, present the data into pages formatted with wikitext templates (instead of complex CSS or HTML) and list and edit them with fully customizable forms. You can query the data to create views and format them in a multitude of ways. All that online, without having to write one line of low level Python, Java, JavaScript or PHP code! Only wiki markups! The same simple markup language that has allowed hundred of thousand of people with no development skills to contribute to Wikipedia!
I challenge anybody to find a CMS offering the same features and flexibility SMW does. Seriously! All the big players in data management, Microsoft, Google, Oracle (certainly not Oracle) still don't offer any system that compete with Semantic MediaWiki in terms of simplicity, from an administrator and a user point of view, to develop a database on the web, styled with templates and editable with forms.
In this article, I want to emphasis the characteristics of a good crowdsourcing web development platform and try to demonstrate that MediaWiki, when it is installed with the Semantic MediaWiki extension, is about the best platform for developing crowdsourcing websites and that it could also become, with little efforts, a very good platform for crowdsourcing of geographic information. I also try to show how fundamental geographic information systems concepts could be transposed to the world of a web semantic database like SMW. I presented most of these ideas during the last New-York City's SMW conference. I’m addressing two kinds of reader: geospatial web application developers familiar with geospatial and web technology but unfamiliar with wikis and mostly with MediaWiki, and Semantic MediaWiki gurus who might be interested in adding complex geospatial information to their wiki.
