We do have a system for people to indicate by abbreviation what they are doing in the swap shop:
[H]- Haves of what you have to barter.
[W]- What you want in return.
{location}-I like to use these brackets for location, but that is fine to use [].
Ebay- Indicates it is an e-bay item. They simply create a thread as outlined above and then do their dirty linking.
There is also a detailed listing for what a thread should contain here:
http://www.dakkadakka.com/dakkaforum/posts/list/247459.page
and also listed there is a what-if crap hits the fan in the Swap Shop under Transaction Report Guidelines.