This widget uses feedburner statistics to list most viewed items. If you want to have data based on google analytics please see my popular post widget with analytics.
You'll need a feedburner account. In your feedburner account you need to activate the awareness api (publicize->awareness api->activate). This allows external access to your feed traffic data.
If you don't have one already, you need to create a free account on google app engine. Hosting your files and web applications on google app engine brings you the advantages of a low latency content delivery network (CDN) which can make your site load faster and for this implementation of the most popular posts widget you need an account. You'll have to choose a domain such as yoursubdomain.appspot.com.
If you don't have it already install python. Download the app engine python SDK for python.
Download the source code of the widget. You need subversion for this. The command for checkout is this:
Go to the popular-posts-for-blogger/popular-posts-for-blogger subdirectory and edit the getfeedstats.py file (use an editor or IDE that knows python, such as eclipse, vim, or kate). Search and replace myoutsourcedbrain for your feedburner uri.
Upload your code with the google app engine SDK. Still in the same directory type:
In your website or blog, where you want the widget to show, paste this code:
Enjoy. Please leave a comment below for questions and suggestions. If you have ideas for any improvements please tell me.