The text above heads would be very useful, but I agree, not in a crowded area, like a market place. I used to play RuneScape, and it was extremely noticeable there, like 100 people crowded in a few meters area, all trying to sell stuff.
To get around this, I think it would be best if something was implemented to stop everybody yelling at once. To keep the real life astmophere, lets consider for a second an actual market place. If someone is yelling out for everybody to hear what they\'re trying to sell, they\'re usually using a microphone. Otherwise, people can just see what they\'re selling when they walk by.
So, I think in a crowded market place/trading area, there could be a podium of sorts where people can shout their wares, and it will be broadcasted to a larger area then when someone is not on the podium.
Also, where people are in a market place (area surrounded by actual shops, banks, smitherys etc) can only sell if they\'re on the podium, as this would be the most crowded, as its convenient to sell items there.
Just some thoughts running through my head, feel free to shoot them down
