According to GenealogyInTime.com's calculation of the number of online visits, FindAGrave.com has become the second most visited genealogy-related website in the world after Ancestry.com. With 143 million grave records, in my opinion, it is likely visited by many people outside the genealogical community who are simply interested in finding a grave of a friend or family member, but it also an important tool for genealogical research. FindAGrave.com was purchased by Ancestry.com in September of 2013. It is presently a free website. The content of the website comes from individual and organizational volunteer contributors.
Information about the graves is contained primarily on a "Memorial" page. The information concerning the deceased is provided by the program's registered users. Here is a typical Memorial page:
The page may contain as little as the name of the deceased and the name of the cemetery or as much as an entire biography with links to other family members who are registered in FindAGrave.com. Here is a screenshot of the links for Henry Martin Tanner.
Normally, the program will contain a photo of the deceased's grave marker. In this case the photo of the grave is on the Photos page.
As you may be able to tell from some of the screenshots, because of its popularity, the website makes money by advertising products and services. Since the information is user contributed and usually lacks any source citations. any information that appears on the Memorial page will be verified by careful researchers. You should always be aware that because grave markers are usually fabricated some time after the death date, the information on grave markers including birth and death dates, may or may not be accurate. But in some cases, the grave marker inscription may be the only record available containing information about the date of birth and/or death. Generally, information supplied by users of any online genealogy program without source citations, including the information on the grave marker itself, should be considered unreliable until it is further substantiated by other sources. If the FindAGrave.com program contributors have supplied source citations, even then, those sources should be checked to verify that the information was extracted correctly.
If you look at the list of family members above from the screenshot of the Memorial Page, you can see that it reports that Henry Martin Tanner had two wives. There is also a list of 13 children, but other genealogical records show that he actually had 17 children. In the FindAGrave.com Memorial the children belonging to each wife are not identified and the list contains some of the children from one of the wives and some from the other. There is also a list of siblings. His father, reported correctly as Sidney Tanner had 23 children. Of those, Henry had 7 full-siblings and 16 half-siblings. The program only lists a total of 14 siblings. The information in the program indicates that 6 of the siblings are half-siblings and the remaining ones are assumed to be those of the listed wife, Julia Ann Shepherd Tanner which turns out to be correct according to other sources. Some of the full names of the listed family members is not provided, even though that information is easily obtained. In short, the information supplied is helpful, but should not be assumed to be either complete or entirely accurate.
Carefully done genealogical research requires a source or sources for every asserted piece of information. For example, the details of the story related by the FindAGrave.com contributor may be found in the following book, available in PDF format for free from the FamilySearch.org Books section.
Tanner, George S. 1964. Henry Martin Tanner; Joseph City, Arizona Pioneer, Born June 11, 1852, San Bernardino, California, Died March 21, 1935, Gilbert, Arizona. [Place of publication not identified.
The information given by the FindAGrave.com program may be informative, but details, dates, places and names need to be further documented.
The location of the individual graves listed for other family members may give some idea of the places where the family lived thus providing clues to additional documents. Unfortunately, the only way to see the location of each of the family member graves is to visit each linked Memorial Page. For example, here is a screenshot of a part of the Memorial Page for Sidney Tanner, Henry Martin Tanner's father.
Some of the same comments I made about the Memorial Page for Henry Martin Tanner apply to this page for his father, Sidney Tanner. As shown on Sidney's Detail Page on FamilySearch.org, he had four wives and 23 children. The information on FindAGrave.com is incomplete.
These observations apply to all unsupported user contributed online websites, including the vast majority of the online family trees. Information is copied and passed around the web without users either questioning its accuracy or completeness. As valuable as FindAGrave.com can be, genealogical researchers need to view it as a starting point for further research.