It seems that the Apple Mac app store has DRM has already been cracked. An iPhone developer tweeted out the way to get any paid app for free which is available in Mac app store and install it successfully without shelling out a single penny.
The developer demonstrated the hack by copying app package contents of a free Mac store app like Twitter and then replacing the paid apps (from pirated store) package contents with that. He is using the .dmg file of the popular game Angry Birds for explaining the hack. This means that you can install pirated apps or third-party apps right inside Mac app store and load it
This was tweeted out from his account claiming the hack,
Steps to hack Mac app store & get paid apps for free [DEMO]:
1. Install the latest Snow Leopard update (10.6.6).
2. Sign into the new App Store (in your dock).
3. Download Twitter, it’s free (link). Now Go to Applications folder and locate Twitter.
4. Right click and select Show Package Contents, navigate to Contents folder and copy _CodeSignature, _MASReceipt and CodeResources.
5. Download Angry Birds ( http://bit.ly/gy9wzk ) and run the .dmg file.
6. Now drag Angry Birds into the Applications folder. Right click, Show Package Contents, navigate to Contents folder and delete _CodeSignature, _MASReceipt and CodeResources. Now paste in the files you copied from the Twitter app .
Done, now have the paid app from mac store (or pirate source) for free.
PS : Software piracy is illegal and this post only for educational purpose.