I have recently started to use the endomondo app, more impressive than my running speed is the fact I could run and still think about ways the product could be improved.
The app has a pep talk function that allows you to send encouragements to friends running however I can’t find a way to be notified when a friend is out running and this limited the use of the function hugely.
Interaction is one of the keywords in the social (media) age, so features that encourage interaction between users should be high on every product owners backlog, not just because we are in the social (media) age but because users like to interact (just look at twitter, FB and the many other apps).
A feature that allowed me to be notified when a friend is out running would prompt me to start the app and send a pep talk. The business benefit would not just be the increase in usage but also help to create communities around the app and it is well known people are less likely to dump an app if their friends use it and there are interactions within the friend group.
So my pep talk to Endomondo: Great app, you are on the right track and just need to push it a bit further and you will win my best app for runners prize.