It's pretty neat. The FAQ's say...
Find a Grave's mission is to find, record and present final disposition
information from around the world as a virtual cemetery experience.
Memorial contributions to Find A Grave should fulfill that mission - registration of the final disposition.
If the memorial contribution corresponds with only the main mission,
then the memorial fulfills its purpose as part of Find A Grave's
Find a Grave memorials may contain rich content
including pictures, biographies and more specific information. Members
can leave remembrances via ‘virtual flowers' on the memorials they
visit, completing the virtual cemetery experience.
Find A Grave is a resource for anyone in finding the final disposition of family, friends, and ‘famous' individuals.
So in theory, I should be able to search the cemetery for my Dad's name and hopefully see a picture of his stone. POOF. There he is! And POOF, here is my Father-In-Law's.
It's cool that as a member, I can upload photos to any name listed. I was at a small cemetery near my house recently and took like 50 pictures and put them in the database. I'm sure that somewhere, a family member is happy to see the stones. And I can add names, called memorials, too. I had to add Dad's, my FIL's, an uncle's and also a cousin and some old family friends.
I signed up to be a photo volunteer. Occasionally, I will get an email from Find A Grave with the name and dates (and hopefully plot #) of someone at a nearby cemetery. If I choose, I can "claim" the request and then go take a picture of the stone and submit it by way of a special link, which emails the requester that it is there.
So since I have a weird fascination with cemeteries anyway, this is a good way to make myself useful!