The Tracker and Codethink awesomeness is ridiculous. We came up with the plans of Tracker Zeitgeist collaborations.
The guys at Codethink (who provide genius) agreed on setting a roadmap so we can know when we can depend on them and believe me its sooner than you think. Tracker 0.7 is faster and better and SEXIER than "iffy" 0.6 (sorry Codethink but just like Stallman I think I am entitled to my STUPID opinion).
Our first draft and plan is to store all our metadata attached to the arguments of the events such as the applications and document metadata into the tracker storage (we are working on that already). Thus leaving the docs and metadata relations to them. Our job is to notify Tracker on specific events what to index etc... so basically we are acting as a data provider. Later we will work with Nepumok to have an event entity in their ontology allowing us to dunp all our event data into tracker, making Zeitgeist act as a hub and event manager. Also we will be querying Tracker with searches where they will the provide us with the URIs that fulfil the descriptions. ROCK ON!