VIOLENCE: Rare but DOES happen is when you do ALL your research into feedback and contact info and even go to the seller's house (which can also happen on craigslist) and when you check it out by going to the "seller's" place, the "seller" will commit violence to rob and may not be above committing murder and torture so that you hand over your money.
NEW UPDATE added 6/07/04: ViolenceBuyer goes to Seller's place to check out the goods and get robbed
VIOLENCE AFTER BUYING ITEM: On any high priced item, if you're able to go to the seller's place and buy the item and take home the item, he and/or his goons can burglarize your house to get the item back to "resell". This is a scam on craigslist with cars.