[davidkatz]

Interesting. Although I tend to agree, it's worth considering one possible difference between cutlery and computing devices: cutlery may have very little usage overlap, and computing devices may have considerable usage overlap.

I actually use my notebook and tablet for reading (even the same content!), I actually use all devices for facebook, I actually use my phone and tablet for gaming, and so forth.

For some tasks, one device type is clearly superior to all others (notebook for typing, tablet for sketching). For many tasks though, clear superiority is hard to establish, or is heavily context dependent.

Ultimately, Steve had it right - for the iPad to succeed, it had to be clearly better for some important things. Strong separation of uses is not required.