Forrester Research does not think it has done enough to promote Apple's keyboardless netbook and has decided that its previous generous declarations about the pointless lump of technology were not generous enough.

It now believes 82 million Americans will be using tablet devices in four years' time. If that is right, then it will mean that tablets will have to outsell notebooks.

The Forrester analyst Sarah Rotman Epps said there would still be more laptop users in 2015, but annual tablet sales would be stronger in the next four years. She added tablets' prices would fall, following the trend of e-readers, where the price of some models has fallen by two-thirds since 2007.

We assume that means that someone will have found a use for the devices which are too slow to be a computer, too difficult to type on, hopeless to read books on, and too heavy to hold to play games or watch movies.