According to the dark art of economics, everything can be valued. Everything can be given a price tag. People may object to this, and do on principle, but sorry, they have done just this for MediaWiki.
MediaWiki has a worth of $3.810.127,- when you assume that a developer costs $55.000,- a year and some other stuff. It was "valued" per the first of January 2006 and as the year is almost gone, it will be worth a lot more.
Another economic truism is that money makes money. Because of the success of MediaWiki more people will start developing MediaWiki. I am not in a position to deny this. WiktionaryZ extends MediaWiki. With new functionality much more becomes possible.
There is one thing missing in this argument. What is wrong is that MediaWiki is a tool. A tool that produces something that is far more valuable. Wikipedia is not the only project that MediaWiki enabled. I am sure some people who understand this dark art of valuation will be able to come up with a better number.
Given that money makes money, it is possible to leverage the MediaWiki generated content. Much proprietary content is not really relevant because it does not get exposure. By making content available it can get exposure. Material was often created to get exposure. By keeping it proprietary, thereby hidden from view, it does not do all that it could do. By making it available under a free license new opportunities arise.
MediaWiki enabled among others Wikipedia. WiktionaryZ has potential. My hunch is that like MediaWiki it will enable the creation of content in a different way. I hope and expect that it will help us to negotiate the release of much content under a Free/Open license and allow us to collaborate with many organisations and people.