Okay, startups since you do not get this..Now the YELLING...
The advertising currency of a social network in order for your startup's mobile application to get huge user increases is the social status artifact of that social network. If your mobile application is not producing that artifact to include in a share post to a social network than your STARTUP IS ScreWEd..kind of simple is it not?
What are the social status artifacts or icons? Picture is the top one overall. Picture and text is another assuming that the social status of the people commenting on said post adds to the visitor traffic. Than it degrades in visitor count effects depending upon the activity of the mobile application and the social network used.
For instance an events mobile application that posts shares of event pictures, event slides, event talks,etc will do better on Linekdin than some of the other social networks because linkedin's social status artifacts are a different mix than say facebook. If you do not even have this levle of marketing understanding as a startup than listen to the mobile developer and let them transform the ap pinto an actual product rather than just a feature set hoping for someone else to save the startup.