What ruined Yik Yak for me was making the geographical areas larger so my University's 'herd' included surrounding cities too. Too much noise. This compounded with the removal of anonymity led to me deleting the application. Wonder if it is possible to run an app like this at cost somehow.
Given that it's just an API serving short text snippets, the hosting costs shouldn't be more than a few cents per user per year. Let's say you're serving one university with 50,000 students, and your hosting costs are $3,000 per year... Just send out an update email once a quarter with a few ads at the end and you've more than covered your expenses.