On another forum I'm participating and moderating on, there is a rule every new poster is required to write a presentation before posting in the trade area. Us moderators over there routinely lock or remove threads due to people not abiding the rules. Some even try to bypass by posting a three line, mostly nonsense presentation.
Fortunately I get a feeling the amount of trade posts on VCF is relatively low, so despite the good web site rankings relatively few try to use the forum as a springboard to eBay or simply a trading place. Perhaps those of us who like new users to appear more devoted to the hobby could start sending PMs with the meaning you have what they look for / want to buy but it all depends on their location. If it is someone who came here to stay for a while, they will get the point.
As a side note, I understand shipping costs depends on state and zip code in the USA, probably within Canada too? A lot of people keep asking about that. Just last week there was a post from someone who wrote he lives in Europe, which to me is just as vague as if not mentioning which state in the USA. As you know, despite the European Union, this continent still consists of a plethora of different countries, all having their own post offices and pricing. Someone selling stuff from within Europe could be living in a high rate country like the UK, Italy, Spain, Norway or Sweden. He could also be a citizen of the Netherlands, Germany or Austria which all have remarkably lower international shipping costs. Plenty of other countries inbetween, so here it is more a matter which is the country of origin than the country of destination. I could afford shipping of a 10 kg computer from Austria but would probably say no to one from Italy.