Looks like the recent $100 million ad blitz for the McCafé seems to be working. The McDonald's experiment in the specialty coffee arena may now have bumped Dunkin' Donuts from the No. 2 spot. But how?

Others caught up to Starbucks. McDonald's tapped into America's coffee obsession. It didn't do it by dabbling in only one or two coffee-flavored frozen concoctions—it re-created the entire experience.

Quality is nice, but people love cheaper. Since the heavy lifting had been done in spurring consumer mocha-frappa-rappa-latte madness, all McCafé had to do was come in and sell that same experience for $2 less. Consumers will settle for "Hey, that's pretty good" anytime.

McDonald's is a juggernaut. It outspent everyone. Over half of its 14,000 US locations is taking part in the effort, and that number will only increase now that McDonald's has had some success with McCafé.