In a sense, um... yeah. Game companies have gotten the art of rewarding down to a science-- every great videogame out there lately is really terrific at balancing the challenge of playing with a suitable reward, whether that be an amazing headshot (along with sound and graphics, usually), epic loot, or just a shiny bit of treasure. That's why we play these things.
So are you being exploited for your money when you hear about Zul'Aman and decide to keep paying monthly to stick around and pay it? No more than when the grocery stores exploit you for profit when you buy food, or when Starbucks exploits you for a tall when you want it. You decide when and where to spend your time and money, and if you'd rather not be "exploited" by Blizzard, you have the right to quit.
Obviously, I don't think what Blizzard's doing is unethical. They're doing their best to make an involving and addictive game. And the reason they're doing that is because that's exactly what we want. Fortunately, as Terra Nova points out, The Age has included a hot nelf pic, so their piece isn't a complete waste of time.
[ via Terra Nova ]