Sto was a planet inhabited by a humanoid species, although other species, such as the Zocci, were represented in the planet's population. Bannakaffalatta was, for example, a resident of Sto — as were most of the passengers and crew onboard a version of the Titanic the Tenth Doctor once encountered.
Stovian society was rather similar to the terrestrial, including unemployment and television shows. The inhabitants of Sto had also an interest in Earth history and culture, given the popularity of the Titanic recreation, although some Sto residents developed a somewhat skewed view of Earth history and customs (such as Mr Copper's take on Christmas).
Known inhabitants of Sto included Astrid Peth, Mr Copper, Alonso Frame, Bannakaffalatta, Foon Van Hoff, Morvin Van Hoff, Rickston Slade, Max Capricorn, Captain Hardaker, the Titanic's Chief Steward, the Titanic's Engineer, the Titanic's Kitchen Hand and a singer.