Information on discovery pages comes from the FamilySearch Family Tree, which is a massive database of genealogical information that FamilySearch users add to the database. This collection of names, places, dates, and memories combine to make the discovery pages.
The discovery pages are accessible through search engines, which allows people unfamiliar with FamilySearch to potentially find their ancestors. This invites more people to come and add the stories of their ancestors to the Family Tree.