The latest patch has been a financial dream for me. A lot of people have been making hefty amounts of gold since the patch. Most of what I've seen are folks who realized in pre-release that inscription would be popular and would cause a staggering demand for herbs. They were smart and stockpiled the herbs and sold them. My guild mate made a 1500 gold profit in one day, that's pretty nuts, but it also took the effort of getting all the herbs. I wanted something easier.
The achievement system also provided for an increased demand in items, I'm mainly talking about vanity pets. Suddenly the non-combat pets in game are like Pokemon, everyone wants to get as many as they can. This is where I come in, as soon as I could log in I went to every horde city and bought the snakes, cockroaches, and whistles. After that I went to the neutral auction house and took a look at the market. A member of the Alliance had the same idea and was posting their pets for 15 to 20 gold. I did the same. Within an hour I had made 150 gold and by the end of the day I had made 587 gold... all from just re-selling pets.
I figured the profits would die out pretty quickly but they haven't. I'm re-stocking every few hours and selling out at 15 gold a pet. There wasn't a problem until another seller came along and undercut my prices. Now I'm all for competition, however there is a difference between competition and market sabotage. All the Alliance pets were 15-20g a piece, I was easily selling mine at the same price, then someone comes along and puts his up for 8 gold. This started a pricing war which lead to me dropping my prices to 2g for a couple of hours. I had the advantage due to being a mage and porting around to resupply. After a bit his sales stopped showing up.
Maybe I'm shooting myself in the foot by posting this, possibly inspiring other people to get in on my racket, but I like competition.