1. A system to facilitate specification of queries or commands, comprising: a user input module that receives a user input; a graphical user interface responsive to the user input, the user interface including a visualization of a plurality of dimensions that form a taxonomy for an associated information space, the dimensions including headings derived from metadata for data items in the information space; a filter generator that generates a filter based on metadata associated with each heading selected in the visualization; and a results component that presents results items that substantially satisfy the filter.