There used to be a time when Auction houses were valuable tools for the speed of obtaining items without having to search hundreds of player bazaars, people could compete on prices and undercut and really wouldn't have to leave their character on overnight to sell something
I used to think they were great too, back when people sold something, someone would buy it, put it on, sell their old junk.. be happy and move on..
but nowadays Auction houses rarely have buyers, mostly they're full of people trying to make a quick dime buying everything they can think of and marking it up heavily
I've seen it on WoW, final fantasy(to a lesser extent, final fantasy's auction houses are great) rappelz runescape... pretty much any game that has an auction house is full of profiteers nowadays.
In fact you can almost guarantee your items aren't going to be bought by someone that will use them.. more like sell them back marked up..
which happens in the real world and its cool and all
but sometimes you'll find one player buys money online and pretty much buys everything in the auction house he can find
Marked up double he'll double his investments minus auction costs.. if they sell..
and it ruins the economy
Sure maybe other people wont be so greedy and it happens all the time as well, you see people undercutting this one person out of sheer spite, I've done it. i hate merchant characters.
but back when there weren't auction houses you didnt have the luxury of finding the best price, you'd spend hours looking for that piece of gear that suits you perfectly from player-made shops. Those were the fun days.
Some of the things that limit profiteering are auction houses showing a list of what the last 20 people paid for an item.. silent auctions which dont tell you what they cost(a la FFXI)
making an item bind on equip if you buy it at the AH
charging exponentially more for each time a person uses the AH to sell something
Comment if you want but if you're one of those people don't assume that I'll give a crap about your opinion or even waste my time reading it.