Several years ago, I posted a picture of my great-aunt with her high school graduating class of 1929. A week ago, another person who has the same picture wrote an actual letter (on paper!) including the names of all the graduates taken from the back of a picture she had. She indicated that she doesn't really do email and doesn't get on the internet that often.
In your genealogical research, don't ignore those people who aren't "really online." Sometimes they have the best, most elusive, information of all.