Thank you for creating this thread in the new users section. It is valuable information.

I had a negative experience a few months ago when sending some Bitcoins. This was in January and the USD exchange rate was just above $6 per BTC. I found a classified ad on bitcoinclassifieds for a HD 5970. The guy wanted $125 for his card, so I contacted him hoping to get a deal. I sent 21 BTC to the address he provided after a few emails. Fast forward a couple days, no more email contact. I sent multiple messages over the next week with no responses. Yep I got scammed, and I hope nobody ever has to go through it. Good luck everybody!!