First reference spotted on September 24, 2008. First arrives in my e-mail inbox as Mom Spam (in my instance, Grandma Spam) with about 10 layers of Forward To's on Tuesday, October 7. 13 days between the time it was posted here to the time it has been forwarded to millions of people by their elderly relatives.
I don't know what to say about this, other than I am sure that somewhere there's a social scientist working on a paper about it. Perhaps the title is something like, "The Elderly and the Internet: The Spread of Social Memes."