the YouTube of data and graphs, Swivel
/Swivel offers free, public and private, data hosting. You can create nice graphs with your data but also search for other people's data. For now this is not entirely geospatial, but when the api is opened up or they update the service, a geospatial component could be added. For now I would seriously question the reliability and accuracy of any data posted there. Below is an example of a graph made with Swivel.