It happens often enough that people still try and some succeed. In reality though, probably about 10% are successful. Most that are will sell quickly to someone they know or someone in the neighborhood. Now just because some are successful in getting it sold, they are not necessarily successful in getting top dollar or the best terms.
As a sales professional for many years before I first obtained my Real Estate License, I didn't think it was nearly as complicated as it turns out it is. There are marketing, preparation issues, safety and legal issues, understanding timing in contracts and ideally negotiating all the details of the contract.
For all the money FSBO (For Sale by Owners) sellers think they save, in many cases they leave much more on the table and leave themselves exposed to greater liability if something goes wrong.
My consistent advice here on Trulia has been to interview a few great agents and only select the best. A great agent/broker is worth more than their commission and a bad one, or none at all may cost you way more than just a commission. Best of luck however you proceed.