Maybe the information needs to be more specific? Also, scouts are already DIRT cheap... paying for this information would be priced... how?
I do like this idea, I just don't see how it could be well implemented - namely due to the research options the Vasari (phase lane) Advent (culture) and TEC (probes) get when it comes to gathering information.
I think that blanketly updating all information about a grav well via purchasing from the black market is wrong. What's needed is something more specific... unforunately, there's not much else. Culture can already be monitored. Phase space can already be monitored. Planets can be monitored over time if you're Advent or TEC already (probes and sacrificing a seeker - or advent cultural dominance).
Pretty much the only thing not available to anyone - is seeing an enemy's primary Trade Lane. Now that I could see buying for a small price, so that you know where to disrupt their Trade, but that's so minor that it's almost not worth implementing.
There's not even a point to knowing someone's construction queue, because if you slip in a scout, you can literally just zoom in and SEE the vessel that's under construction. Pirates could be useful sources of information if you can't GET a scout somewhere... but a scout w/ unfettered jump drives and any other upgrade they can get is going to be able to get around a hell of a lot better than a pirate scout.
As for selling YOUR scouting information to other empires? Good call, depending on how you set your price it could help or harm your relations to the buyer too. I just don't see the merits for Pirate based scouting when you consider how the pirates function in this game.
Also, the scouting bounty mission thing is pretty cool - as long as it's done with your own ships, as it could serve as a good means for improving relations. Perhaps one of the missions will be requested of you, or requested by you - while the other one is always offered by someone (as an item for sale, never as a request)
-Itharus