Okay. I think one reason for no public giveaways is it can get out of hand. Deals fall through, people feel left out, and it can change things/mood/the feel of the Yard.
I agree with what Which Dawg says above.
I don't think it's happened yet and don't think it would in the near future, but in the middle distance as more and more people join the 'Yard I could see it happening.
Here is an idea, since Scrapyard is a stand alone comunity (Busse and Swamp Rat each have 2 forums) I am not saying put up a for sale thread but maybe an available knife thread so for example if I bought 2 S5s and realize I don't need 2 I can put a post up that says I have an extra S5 then an interested party can pm me or if I am looking for say a DogFather I can post that I would like a Dog Father and anyone who might have an extra can pm me.... just a thought. Don't have to list prices and whatnot, if i want to make a profit on my blade I will sell it on the exchange or ebay but maybe I just want to help a fella dog out. You can keep it tacked at the top, make the rules simple, no prices listed and ask the Dogs that if they are looking to turn a profit on their blades please sell them in the appropriate sites, it could be a thread called "Help a Dog out" or something like that.
There's always BF (which I'd guess most of us here belong to) and the Bussekin Exchange mail list/group that Andy created for that sort of thing, so its not like not having it here will stop people from doing it if they want, but not having it here will may well help preserve the 'Yard sense of community, which is just outstanding and imo well worth protecting.