while I am sure that there have been a few sales here online, your best bet if you want to sell a vehicle, is in addition to listing it here, do the local newspaper adds, Craigslist, and other local publications.
Craigslist is fairly decent after you weed out the scammers. I sold my 94 Olds 88 w/ 178,000 miles on it back in June. got a few scammers, a few offers to trade for junk, and a few legit offers.
The issue with selling a vehicle on TRS is not everyone lives in your area, and most people will want to look at it first hand. So you will probably get quite a few "I wish I were closer" or "nice truck" responses. look at them this way, most of them especially the "nice truck" responses are a free bump for your add to the top of the screen.
another thing, for those that ask for mileage and other info while not being "interested" may have found out that your truck is not in their mileage range, or you have options that they do not care for (such as auto trans, or 4x4). Remember, the more info you post on your truck, (mileage is extremely important) the more info people will have to make their decision. They are helping you out on getting more info into your add. ultimately this will help sell your truck.
AJ