iPadkneesup.com
ipadkneesup.com
ipadkneesup.com
In fact, writing at all while standing or sitting without a stable surface in front of you is pretty awkward, and with a normal notebook/laptop, it's damn near impossible because of the bulk of the thing.
Unfortunately, it's about 100X dorkier.
Update: lie in bed and browse one handed, but roll to sit on the edge with crossed leg to post. Again unconscious and noticed after the fact.
First annoyance: Have to go back to my laptop to copy-paste and quote another HN post for a reply. Can't double-tap to copy!
Solved by one second of tinkering: doubletap-drag to use copy-paste!
Yet I'm pretty sure this isn't a quirk of their advertisement, though they do want to convey relaxation as much as possible. Apple is trying very far to avoid demonstrating/emphasizing the natural usability limitations of tablet computers.
On-screen typing for a tablet while at a desk is rather awkward since the natural tendency is to hunch over it to see beyond your hands and look down at the rest of the screen. That's not really comfortable and doesn't look very natural.
Even during casual use, any two-hand operation of the screen would need some sort of support behind it. Since setting it on a desk is awkward (per above), you'll need your lap to brace a tablet for those operations.
I assumed Apple is just trying to keep the attention focused on how awesome their product is rather than on the usability disadvantages that are inherent in such a product.
The fact that people noticed the "knees up" nature in their advertisement means Apple failed somewhat at making this posture and behavior appear natural. I bet the creation of a site like this is making at least one of their marketing guys sadder than he was before.
Edit: I just got my iPad. First comment: it's heavier than I expected after using a Kindle so much-- you'll want to brace it behind something for long-time use.
Putting my feet up on a table RIGHT NOW.