I think that there should be a new category as there is : FT,ISO,PC; this should be a "Trade list" mode where :

-people could edit their first post (avoiding flood with updates and offers for sold items)

-Only one Trade list per member.

- special window for trade list ( So they wouldn't sink because of fast trades)

This could avoid some flood, make the forum easier to read, simplify transaction beetweens players in general.