In Fire Upon the Deep, the Vrinmini Organization recovers Pham Nuwen from, what the head of the Org (Grondir? Grondor? I don't know how to spell his name...) describes as a Slow Zone Dredge. Ravana, I believe, goes on to state that the races that send dredges (or other ships) down into the Slowness are a bit weird. I don't have my copy of the book on me, so I can't bring up direct quotes. Sorry about that.
Now, my question is; what's the point of even sending down a ship into the slowness, if the people who sent it will never see the fruits of their labor, or see the ship return? I mean, even weird people do things with purpose at times, right? What would any civilization or group of people in the Beyond gain from anything in the Slowness?