It could be interesting to think of implementing this with indexing events. These may be events that are linked to one another in some manner forming a mesh that indexes relay data across relays.

If we can add monetization by charging the readers of these events it can insentivize indexers to create such events and push them to relays.

Then "all" that is left is to think of the data scheme that allows mashing events into various indexes of data across relays.