I remember when this new thing called an answering machine was invented and people were so freaked out by them at first. I heard people say so many times, "I'm not leaving them a message on that machine! If they need me, they can just call me back!" As if the person was supposed to intuit that someone had called and not reached them.
Then people were a little freaked out by computers and emails. Of course, I'm mostly talking about people who didn't have to adjust to these things because they didn't have to learn for business purposes. Ok, mostly, I'm talking about my mom here, but honestly, don't we all know people to whom the idea is still quite uncomfortable and to whom there really is little point in sending an email?
And forget about the "internets", as George W. Bush one famously called it...them. I can still remember just within the past few years hearing someone say, "I can probably plug a computer in, but after that, I wouldn't even know what buttons to push to go to a website.
And I still know people who are afraid to use Facebook for any number of reasons, the most prominent being that the CIA monitors everything we do there...and the Russians too. Seriously. And this includes someone I know under the age of 30.
All that said...I'm drawing the line at Tweets. I went to the site, signed up and went back once a month later. Sorry - I just don't get it...them.