We Need More Writers!
On June 3rd there was a patch that adjusted the trading post in this way:
The listing fee can no longer be avoided by listing an item at a lower price than the highest buy order. Items priced lower than an existing highest buy order will now be sold at the lower price. The player with the highest buy order will receive the item and be refunded any difference in price.
What's this mean? ~Kevin"
Actually this is a horrible explanation of what they did. On our forums, we've known for years that you could avoid the listing fee by selling items at 1 copper. Let's say there's a buy order on an item for 1 silver minimum. You sell at 1 copper and it will get bought up by the 1 silver guy but only cost you 1 copper in fees instead of 15 copper. This was an easy way to avoid the fees that was in the game since beta.
Bummer, this will hurt the min/maxers trying to make as much gold as they can on the trading post. In a game like Diablo 3 when we were selling items for real money, I would have exposed such a bug to the public. But in Guild Wars 2 we are playing for fun, so such a minor bug seemed like a fun reward for those that found it.