It's a pretty self-explanatory thing, but since it's a feature on the system we might as well use it. Right now it's just in the Marketplace to make your sales threads stand out a little more on the list.
When you go to start your thread you'll see an option to add a prefix. It's pretty basic. For Sale, For Trade, and Wanted. I've also added 'It's a Steal' and 'Ammo' for Steals and Deals and the In stock Ammo section since those tend to be time sensitive.
I may add more as we go, but we'll see how these do.