The short answer: the free app provides you with user-generated content for one train (or bus) line. Our premium service gives you more features. Premium was previously packaged for the web as Inside Track. It is now an app, called Clever Commute Premium.
So where does the free app fit in?
It gives you alerts from your fellow commuters on one train (or bus) line. The implementation is similar to a newsfeed in Twitter or Facebook: the app shows you recent alerts on a scrollable page. The app also has other great features such as push notifications (optional, of course) and the ability to change your profile (in the app) so that you can see what is happening on other lines.
You can get the app via Apple iTunes or Google Play. Info/screenshots/video is available here – http://clevercommute.net/