Some members sending me pm about trading and other services and other bitcoin talk service.. how can i know this member asking me real or want to scam with me...
Too many the people are promoting their service are having a high chance for to be a fraud, someone is trusting will not for directly making any PM in your inbox. I guess this is just used by the people are having a low trust level, don't trust someone in this cases, without making any PM for you the trusted person are already having a lot of the people are know him in this place.
Yes personal messaging is the best way to be safe in scammer. You need to know who is the one you will make a transaction with because in trading there is no physical currency that you can see. In transaction some trader want to have the trade first before they pay, because somehow they also think the same way if you are a scammer or not. And if you have some past transaction in some people you can used them to know who is the person to trust on or not.