If you want a proven game formula, then this is it: Find a gameplay type that people love + tweak to improve it + add in a great theme = profit.

Brilliant:

1. They found gameplay that was exciting and PROVEN.
2. They tweaked it by adding more content.
3. Then they chose a much wider “theme” that is very prevalent in the App Store.

I love this: "Sure enough, I open up Clash of Clans and it’s the EXACT same tutorial. I mean, literally the same thing. It moves at a smilar pace, the objects are similar and gameplay is the same. You start off and immediately are being attacked. You have to setup units to defend your colony, then after beating them, you magically fly over to their colony and defeat them."

This is a good point, too: "The first social games were just about managing resources. There wasn’t any actual REAL game play… it was just building and waiting. Even though I have built a couple, I had a hard time actually getting into it. There was absolutely no STRATEGY really involved... [When] people to battle each other in real time, it makes the game 100x more interactive and fun."

And: "CORRECTION. It’s $750,000 per day!" Unreal...

The game is also very similar to evony (evony.com) except its a little easier to play which made it a great adaption for mobile.

That actually seems to be key: easier for mobile = more people will play.

 Exactly, but there are other keys that are really important.  You touch on the strategy component, but because you can be attacked at any point and lose resources you log in a lot more than you do on other social games.  Since there is this competition, people tend to spend money to build up faster to protect and attack others.

These aspects drive utilization and monetization of the app.

The ease of play makes it better for the casual gamer.  Evony was so devastating when you lost because you could lose one of your castles, heroes, etc and gets to the point where the game becomes a job.  Clans minimizes your resource loss and rebuilds everything for you, so you are not completely devastated when you lose.

It's the right formula; let's see how many others follow it.