I think its a pretty solid bet. I mean when's the last time you posted to your neighborhood BBS, or on aol. Remember geocities or even myspace (though its still there, who really uses it, really). You can't even get access to your own older tweets.
Oh, sure, Twitter and Facebook will probably go away. I was mostly looking at the inclusion of the Internet.
We figure it'll happen someday. Of course, it may be centuries in the future when the roach kings rule, and our paperback book may not last that long.