I'm a little sad I missed out on Yik Yak, tbh. I think the idea of interacting with people within your proximity has power. Whether it just be casually BSing with your neighbors, or having conversations about a sports event.
I'd prefer if it were anonymous/pseudonymous with effective location fuzzing, though. But that could in theory include profiles with details you're willing to share with randos. Could have augmented reality (AR) uses as well.
As long as you control the information and have the ability to shut it off entirely, it could be useful.