The Ultimate Airfare Hacking Guide
nomadicmatt.com
nomadicmatt.com
Also, having seen some actual creative bookings (not full-on penetrations, either), calling this "hacking" is a stretch too. Google things like "fuel dumping" to start learning about actual airfare hacks.
To add at least a little value: matrix.itasoftware.com has found trips (e.g. Amsterdam-Tallinn) for me that the local (Dutch) travel sites didn't. I was pleasantly surprised by this.
Anyway, if you want to go the elite status route, you can't be a price comparer. You have to value the benefits you'll get with your status over saving $100 on your next flight. Because 33,000 miles on United, 33,000 miles on Delta, and 33,000 miles on American gets you pretty much nothing. But 100,000 on one of those gets you quite a lot. (I personally lean towards the Oneworld airlines because AA chose good partners. Even if you are flying on AA, you can still use BA's lounge. And they are very nice. Cathay's lounge in Hong Kong is also amazing. Shower rooms, nap rooms, etc. Great way to kill a layover after a 15 hour overnight flight :)
Not quite. See http://en.wikipedia.org/wiki/Arbitrage
I think the way you are looking at it could cost you a bit of money if you are not careful.