Felix asks, “I was just wondering when it was appropriate to use people as opposed to persons.”
There is some confusion regarding the two terms, especially because their meaning and usage suffered a mutation along the centuries. Both derive from Latin, but from different words.
Person derives from persona, which refers to an individual. People, on the other hand, derives from populum, and it refers to a group of persons sharing a culture or social environment.
Person is a singular form, and its plural is persons. Over the time, however, many writers started to adopt people as the plural form of person, and nowadays it is widely accepted. Notice that legal and very formal texts still use persons as the plural form.
One distinction that was proposed was to use persons as long as there was a countable number of individuals (e.g., 67 persons left the school) and people when such a number was large and indefinite (e.g., the people left the stadium quickly). The rule did not catch on, though, and some writers still use people even when there is a definite or small number of individuals.
Finally, people can also be used in the plural form (e.g., the peoples of Asia) when it refers to the different cultural groups that live in a certain region.