Have people of all times been struggling so hard to keep their growing knowledge and skills from seeping out of their brain, or is it a new phenomenon? Maybe it works very much like the mechanism of spending money - the more money you earn, the more money you spend, and the more money you wish you had, so you could spend it...
Haven't researchers shown that through regular exercise, you can make the neurons in your brain proliferate, thereby increasing the efficiency of it - although then you have to start worrying about your brain coping with all the self-created dead ends and mysterious connections maybe, like using Linux instead of Windows? (My brother would probably protest).
My flatmate in Bremen told me of a regular café customer who said that since his retirement, he would spend at least one hour each day solving complex maths problems, in order to keep his mind alert. But I can hardly manage them now, and I dread to think what it's going to be like in 40 years time... anyway, he was a maths teacher.
All this because today I have been using Oxford's online dictionary (please excuse the product placement), and it generally stresses me that everyday they post a new interesting/baffling word, which makes me think I could study English til the end of my days, and not be finished. Never mind Arabic!
Conclusion: the www is a double-edged sword.