IIRC from the annotations (it's been a while), Vinge did not intend that Twirlip was right about everything; Twirlip was merely meant to a representation of the weird things you used to get on Usenet. But it worked out fairly well. (On the one hand, this might technically be a spoiler, but on the other, I think in practice even knowing this tidbit won't actually give anything away.)

(I'm glad someone linked to this. I actually bought the annotated edition a while back and was reading it back in the Palm Pilot era, I think, but I've lost it and never quite finished it. So I'm happy to see it and have no qualms for myself about grabbing it.)