Dividing the work of collecting a substantial amount of data into small tasks that can be undertaken by volunteers. Some examples: Wikipedia is a crowd-sourced encyclopedia and Galaxy Zoo was an early example of crowdsourcing scientific data, by asking non-expert volunteers to classify galaxies based on their visual appearance. NOVAM was a service which allowed the public to verify or correct official data on the locations of UK bus stops, crowdsourcing about 18,000 corrections.