I used to base my opinion on the avatar in the naive assumption that they were representative of the person... i.e. if it was a female avatar then it was a female poster, Domme or sub picture means Domme or sub poster and so on. Unfortunately, that is not the case (though it is in many of them).

Now, if I am not sure, I go look at the profile. If you right click on it you can see it in a new window to save closing the one you are viewing and the chatroom 'view profile' option does that automatically and it is usually the chatroom I need to see who I am talking to more than in here.