That word "computer", I don't think it means what you think it does ...
"The computing environment is changing too fast for that. If you were looking to construct a GCSE for three years hence what would you include in the course? iPad? ChromeOS tablets? Android tablets? Android phones? iPhone? Kindle?"
Them's all appliances, not computers.
"And what about facebook, flickr, youtube, google, twitter and ebay."
That's all marketing & advertising, and has nothing to do with computing.
"What about the ones that are going to dominate our lives in three or four years?"
That word "dominate" ... Some of us haven't succumbed to the mass media.
"And what, most especially, what about the course module dedicated to The Register?"
::snort:: Redtops are redtops ...