When isis was blazing its trail of gang pillaging, it did a VERY provocative thing; it seized oil production. At that point it seemed clear to me that Obama should stop their access; he didn't.
The black market soon became their dumping ground, greatly under-cutting the price of oil. Imagine what happened to their bankroll. With said bankroll, imagine now the ability to recruit, particularly to young, naive, dirt poor boys.
There are two important aspects to isis oil. First, getting the oil is one thing, refining is another. How is isis accomplishing this? Turkey, specifically, Erdogan. And who controls oil refining in Turkey? Erdogan's son, Real.
Note the wackiness of this sitch: Turkey is a nato country, fighting isis on the Syrian border, and yet is providing the key element to isis' ability to... well, to do just about whatever it wants.
Let's not forget that Erdogan is a psycho to the point of terrorizing his "own" peeps, the Kurds, who in fairness are punked everywhere they are. Even more, think about a recent Forbes (Forbes!) article that pegged Egyptian despot psycho Mubarak's worth at a possible $700 billion!!! It'd be a ceiling hard to approach, but the Erdogan's bankroll must be EXTRA large by now. The lesson here is that, just as isis' fuel is oil (a convenient pun indeed) how can it be any less so for a Mubarak or Erdogan?
The second major point is who does isis' - and Erdogan's - banking? We know that in the receding pinpoint of EM08 that banksters have ADMITTED to laundering for drug cartels and Iran. These are the biggest players around, HSBC, RBS, Standard Charter, JPMC... with that kind of complicity, aiding and abetting, it's no wonder isis is what it is; a bunch of punks living out their fantasies, just as unicorns run by 25 year olds in Silicon Valley that ***lose money*** but are valued in the billions are capitalized by market forces.
In a time long ago, and long forgotten, there was an historic scandal: Watergate. Then Deep Throat insider/informant and now known Mark Felt uttered the infamous words, "Follow the money." He was right then, and just as much now.