When I introduce Find-A-Grave to participants in my "Introduction to Genealogy" course, I will ALWAYS remind them of the vast differences between primary sources, secondary sources and what I would refer to as "Volunteer Sources". Much like family trees uploaded to FamilySearch.org or Ancestry.com, the information can be helpful but should only be used to point someone in a direction that may be useful but at the same time, may cause confusion. The point being that you have to factor in the GIGO equation: "Garbage In = Garbage Out"! Look for the suppporting documentation!!