I built an app that does this, but this one does it better, so upvote and high five on the execution and App Store feature 🙌 --> only thing I would recommend I suppose is adding GPS in order to cross-reference step count with movement so as not get caught up in a dog-collar situation (literally, put phone on your dog's collar and throw a tennis ball for twenty minutes...)
I like the idea of competing against strangers, especially ones with comparable step counts daily. That would help me try and go above and beyond my normal steps. I run each morning and walk my dog in the afternoon, and have a feeling I would crush most of my friends that don't move their desks everyday.
Corkdork
CollageMo
