Just a note before I reply specifically. I'll say it again; non-geeks want to do the same things that geeks want to do, they just won't tolerate a high threshold. If something is cool and it is also easy enough to do, everybody, even non-geeks will do it.
But, when handheld devices can easily play the same video that plays on big-screen TVs, and it is easy to move video around between devices, and the video looks nice, you'll see everyone watching last night's episode of Lost on their handheld devices on the way to work on the bus.
My contention is that everyone will use the social networking side of a mobile device if it is easy enough. A quick glance at your handheld will tell you (roughly ) where your friends are, what they're up to, whether they're interested in hanging out tonight...
Do you find that people want the contact list syncing thing for non-work purposes?
As for video phoning, it is one of those applications that just has never taken off. I suspect we'll all want the option of video, but we'll rarely use it (except, well, in the situation you gave above ). I think as it gets easier to text message people, even voice communication will drop a bit. We're seeing that already on mobile phones.
Again, this is one of those things that hasn't really taken off yet because it has too high a threshold. Recently, people started getting handed free newspapers at the station in the morning here in Vancouver, now suddenly the bus is full of people reading the newspaper (celebrity and sports news, mainly, but still). Before, I rarely saw people reading the paper on the bus. I hope that we can get this worked out. I want to see people use less paper, and ubiquitous hand held devices with nice big easy-to-read screens seems like a good solution.
Threshold issue again. If you make it easy to share, store, view, and get prints of your photos and videos, and they're decent quality, everyone will be using it.
That's very interesting. Online shopping while sitting on the bus... Why not? I think we'll see the web evolve to meet mobile needs when more people are using it from their handhelds.