MediaWiki is the software that serves the content of the Wikimedia Foundation (=WMF). The Wikimedia Foundations is proud to bring us Wikipedia, Wikinews, Wikiquote, Wikibooks, Wikispecies, Wikisource, Commons and of course Wiktionary.
The MediaWiki software is really scalable; Alexa has Wikipedia noted as a top 20 website in the world. This is a stellar performance of the development team that is behind MediaWiki. The team consist mainly of volunteers; their main job is to have the servers of the WMF running as best as can be.
The MedaWiki software has a rich functionality; all the WMF projects are using UTF-8, the software is used for many languages including right to left languages like Farsi, Hebrew and Arabic to name a few.
The Wikidata functionality is to be part of the MediaWiki software. The intention is that the combination of relational data and OmegaWiki translations will allow us to maintain data once and do this well. Of particular interest will be statistical data and data like the names of presidents, mayors etc. This kind of information is held in many Wikipedias and this will allow us to maintain the data once and thereby provide more timely updates.