Ask Slashdot: Knowledge Management Systems?

Tom writes: Is there an enterprise level equivalent of Semantic MediaWiki, a Knowledge Management System that can store meaningful facts and allows queries on it? I'm involved in a pretty large IT project and would like to have the documentation in something better than Word. I'd like it to be in a structured format that can be queried, without knowing all the questions that will be asked in the future. I looked extensively, and while there are some graphing or network layout tools that understand predicates, they don't come with a query language. SMW has both semantic links and queries, but as a wiki is very free-form and it's not exactly an Enterprise product (I don't see many chances to convince a government to use it). Is there such a thing?