The advantages are that you at least know you have control over the price you're willing to sell the car for. When you go to a dealership, they can manipulate the price they tell you you're getting with the trade-in value, the discount on the new car you're buying and the finance rate they are charging you. It is very hard to get the best out of a dealership because they make things so easy for you to dump the real value of your car into a finance package.
However, when selling privately, you have to deal with not only posting an ad, but trying to filter out the type of people who may show up to buy it. There are several horror stories of people who were robbed, injured and even worse when people came out to buy their car. The real fear of thieves "casing your home" is not only valid, but you can read stories all the time about a Craigslist seller who got robbed when trying to sell their car.
Many times there are promises over the phone of cash on the spot and "we'll be right over" that make it sound too good to be true. I would also recommend that you never show a car in the dark and you never let your wife or kids sell a car when the man of the house is not home. You may not ever want to sell the car alone either. Here are a few links to horror stories involved in selling a car online: Glendale Robbery and Woman Robbed at Gunpoint.
Now, there is one surefire way to be safe and get the most cash for your junk car or a car that is running or driving and that is to sell it to an insured car buyer that is located in your area or a national buyer that has bonded partners in several markets around the country. There are a few of the national auction houses that can pick up cars in every city in the United States and they usually will write you a check because they want to make sure they aren't robbed of cash when they get to someone's house. Robbing tow truck drivers that are carrying cash is a new trick popping up in several inner city neighborhoods across the country.
