Nobody around me who is over 40 seem to know about exposé, even people (all scientists!) who have been working on macs since the dawn of time. Finally, I had to put big fat labels on F9-F11 keys with explanations as to what each one does when pushed, but to no avail: each time when they want to switch an application they minimize every single one of their multiple windows, one by one. Every time they "forget" that the F9-F11 keys were even there

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Oh, and don't even get me started on the use of the Alt-tab key combination - it is "too complicated to remember"!
And by the way, PC people all think that exposé is a gimmic. Admittedly, it took me a couple of months to get addicted to it completely...