I am considering developing an app that allows you to organize your runs with friends. Basically, any time you want company on a run, you put it on a calendar that only those you've approved can see. If they want to join then they can "opt in" to let you know they'll be there. Of course, you could limit what some buddies see if they show up to your runs too often.
Is this something that you would be interested in using? If yes, what would you request from an app like this? If no, why not?
Thanks!