Yes unfortunately i lost a lot due to some fuckhead scammers, I am now very suspicious of scams.
Yeah majority of users have been scammed by some person or got scammed by investing in any ponzi sites so now I have decided to stay away from those sites.
I don't scamming site is the main problem for loosing bitcoins, i think there are allot of people who lost allot of bitcoins and that is because when you lose your password for a wallet or something...
If that is the case then its an worst way to loose bitcoins, I mean how can be someone so careless that he cannot take care of his own money, I have never lost my coins in that manner.