Lars wrote a post about his faceted search option for Mindquarry tasks in version 1.2. By his description you may get easy a glue how it works. That seems to be a simple (but useful) step to the task feature.
But faceted search is a solution on top of technologies. Microsoft is developing that right now as a solution to compete to other search engines like Google.
Faceted search is an option to the general search dilemma, that you (the searcher) must have exact knowledge about the search content description to find exactly what you search. For example if you search a suitcase with tiger pattern you would get the operating system “tiger” (Mac OS) , the animal “tiger” and much more overwhelming information.
Even plain full text search is not a perfect solution. try to search a telephone-No, like 777-6330, you’ll get results with telephone-, article- and stock- numbers.
Faceted search is different, it shows you structured options according to the implemented meta data. So you are able to refine your search results step by step in a guided manner, even when you not now the detail of the content. For example you may search for music and get containment options like “jazz, blues, pop, classic…” to limit your search results.
A very good short summary to faceted search you find here.
Lars was by the way able to implement that within one day, because of the open architecture of Mindquarry. This will allow us to implement faceted search in other components to, like in the file synchronization, the conversations section and the wiki too. We’ll do that step by step and Mindquarry users will enjoy new modern features within short time cycles. Stay tuned.