GeoExposures is a newly developed crowd-sourcing web site for recording temporary geological exposures in Great Britain that might be lost to science. It has been developed and deployed by the British Geological Survey (BGS) using the Ushahidi Crowdmap service. Geological site information can be recorded and uploaded using a smartphone or via a personal computer to the common-access web site. Geological data is recorded using a pro-forma and is uploaded along with digital photographs. Support is provided through linked web sites including Google Maps, BGS digital geological maps, the BGS Stratigraphical Lexicon and BGS TimeChart (geochronology). As a contribution to citizen science, GeoExposures will enable the geoscience community to contribute to recording and preserving important geological information. GeoExposures is made available under a Creative Commons licence. As with other citizen science initiatives, the information and photographic records are available to the community and copyright is not vested with the individual respondent or the BGS.