Maybe something like this could work, if you want to make the Station/Streets/Bars a gathering place where you can pick up rumors:
The game produces something interesting randomly in some sector, for instance an asteroid that is rich in a rare Ore. The location of this asteroid can only be detected by a player nearby: only when a player comes nearby, will the server start to send packets about this asteroid to the client. The player can decide to mine the asteroid himself, and hope nobody bumps into it too, or he can go to a Barkeeper (or any NPC) on some Station and sell it to the NPC for some serious Gold by giving the Loc coordinates. The moment the location has been shared with the NPC, other players who may bump into the Asteroid can not sell it to an NPC anymore.
Now this Barkeeper/NPC has a fresh rumor. This rumor will stay a few hours on this NPC. Any player who checks this Barkeeper will learn about it, and can decide wether to hunt it down, or decide that it may already be old news. Some people will check in the chat channel, but this could be unwise if its actually a freshly sold rumor. The Asteroid also has a limited lifetime.
Problem I see is that players most likely will sell it directly to the highest bidding player. This is probably a more interesting mechanic anyway. I guess you could find some contrived way where the NPC is needed as an intermediate, for instance by having the Asteroid disappear directly after discovery, only to return into existence once the loc has been shared with an NPC (maybe we could call this "claiming the find") but I could see people auction the find in chat anyway, and then agree to meet up with the highest bidder near some obscure NPC and quickly do the transfer of info, using the NPC. Kinda cheesy that way.
Any suggestions?