I think of it as more like being able to transition between devices in a logical manner. Your example of Lightroom 3... yeah, that's not going to happen. It's the idea of being able to transition things such as a browser state between objects, and I think this can be done easily on a software basis.
As I mentioned, I'm pretty certain Firefox has a feature like this that lets you share your tabs across devices.
I actually have an issue now where I can't even transition between iOS devices without a ton of hassle. Let's say I'm playing Kenken (Sudoku + Math) on my iPhone, and now that I'm home, I want to play it on my iPad instead. I can't do that... there's no way to transition my game state between two iOS devices unless you use some crazy jailbroken work-around or the game supports sharing saves via iTunes (very few do this).
I've been complaining about this for awhile now.
