Forum Moderators: open
I, for one, just don't do that much anymore because I visit these forums as a sort of break away from my regular work and just find it too frustrating to mess with.
If we allow anyone to post information that leads people to one of their projects, then crafty marketers take advantage of that situation (and in volume, I might add.)
Because of our policy, it's true that we all need to work a bit harder to explain our topics in words and snippets of code, instead of just pointing to an example page. But that extra effort we take benefits everyone who uses the forums. Our technical forums are not online just to resolve one person's problem, but to do that in a way that helps many people -- establishing a knowledge base, in other words.
Linked pages will change, sooner or later, and that can make threads that depend on links difficult to follow. But a conversation that doesn't depend on links is valuable indefinitely into the future.
Also, we found we needed to tighten up on links as we grew in prominence over past years. When you have much of the world's media reading your pages regularly, then marketers will try almost anything to get those eyeballs - including dropping their url in "help" posts.
This makes it impossible to decide who has a legitimate request, and who is looking to get their url on a busy forum. And then there's the folks who leave a link, then switch that page to something nasty after a few weeks. So the only workable decision, given our volume, has been that we will only accept links to known authority sites.
See Professional Forum Spammers [webmasterworld.com] to learn more.