The subject disclosure is directed towards co-located collaboration/data sharing that is based upon detecting the proxemics of people and/or the proxemics of devices. A federation of devices is established based upon proxemics, such as when the users have entered into a formation based upon distance between them and orientation. User devices may share content with other devices in the federation based upon micro-mobility actions performed on the devices, e.g., tilting and/or otherwise interacting with a sending device.