if a guy writes to give u compliment and thats it, there is no harm. if a total stranger wants to pick u up, ignore him.
but there is another side to this story. many of our regular or less regular female members if went through an emotional crisis or just needed virtual hugs, they started a thread and expressed their feelings. this way, virtually or not, brought themselves in a vulnerable state. so surelly there have been and will be guys who will try to take advantage. im not saying either of u girls should stop having such kinds of posts, only u have to realise there is this "risk".
there was some time ago a thread about who is more deceiving, men or women. well my dears, we are. and there are plenty of examples of chicks who show up for a short period of time and want to make the max of it, so either play fragile lil babes who need comfort or bust in with some "hot" attitude. and they DO want those PMs.
or just simply u caught the attention one way or another of some guys who try their luck.
so my advice to u is to be normal otherwice and a total monster in Romance