Teenage Twitter and Facebook Addicts

Dear Cyber Sorter,
I have two teenagers, 13 and 15, who are addicted to Facebook and Twitter. It has got to the point where it’s hard to drag them away from constant updating and newsfeed monitoring for a hot meal and an occasional wash.
This Christmas my parents-in-law will be joining us. The children love their grandparents but their childish adoration and fascination with them has given way to adolescent nonchalance.
They are open and gregarious to their friends, with whom they exchange up-to-the-minute bulletins of their lives and interests, but anyone who doesn’t use social media doesn’t exist, and to their way of thinking probably doesn’t have the right to, either.
I tried putting a blanket Christmas ban, but there was an outcry (oh, the drama! “Fine!,” yelled daughter, “but you will be responsible for ruining not just my Christmas but MY ENTIRE, LIKE, LIFE!”)
Help!
MD

Dear MD,
The first seven words of your e-mail were enough to alert me to the fact that you have a serious problem, or two.
Fortunately there are a couple of solutions;
1) Friend them on Facebook and follow them on Twitter. Then interrupt their conversations. Write on their wall with attention-grabbing messages such as “Please come downstairs for your dinner now, you ungrateful little whatsit. PS Justin Bieber rang for you but you didn’t hear me call.”
2) Leave them to it and after Christmas dinner is over lightly suggest that the little darlings show granny and grandpa how to use this wonderful newfangled technology. Then hide in the kitchen with a large glass of wine and that new novel you bought yourself.