Sto was a planet of mainly near-Humans, 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. The fact that the Titanic was bound for Earth suggests that Sto might be a relative neighbor of Earth, and thus in the Mutter's Spiral.
At least one of the planet's indigenous races, at some point in the past, apparently worshiped a god named Vot.
Cyborgs were generally discriminated against by the dominant culture of the planet. However in the early 21st century laws were made allowing them more freedom, such as marriage. (DW: Voyage of the Damned)