SatNOGS, the Satellite Networked Open Ground Station (mentioned in this answer) appears to be a distribution of independently maintained amateur DIY satellite receiving ground stations, linked by a single network.
How is it run? Do members log in via the internet and then reserve a time slot on whichever station they would like to use? I noticed that there are amateur radio callsigns associated with the stations. Does this suggest that uplink capabilities are available in addition to downlink?