VOIP and cell seamless switching

According to this article on CNN.com, Motorola is building this capability into its next generation of cell phones.

The article doesn't give much detail on the value proposition for the cell service providers, but here are some of my thoughts:

1. Current cell plans with "nationwide roaming" program your phone with a preferred provider list for geographic areas. In other words, if you have one of the AT&T Wireless nationwide roaming plans, you will not roam onto Cingular's network unless AT&T absolutely provides no signal in that area. Similarly, I think it's safe to assume that a similar type of preferred list could be built into the phone for VOIP -- a TMobile phone should only work on TMobile hotspots unless no TMobile hotspots are available.

2. Data is really the new dollar proposition for cell providers. Accessing the web, reading and sending e-mail, picture mail, sending pictures and videos, watching TV, instant messaging, tethering your computer to your phone to access the Internet etc. are all very data intensive operations. Combine those data operations with wireless hotspot operations, and there is a potential fortune to be made. Currently TMobile offers wireless customers discounts on monthly hotspot service, but the advent of WiFi and cell combined devices should make this operation more seamless (whether charging for data in chunks or with unlimited plans).

3. It would be really nice to be able to use your cell phone at home with your own wireless network. Either the software on the phone is going to have to prevent this, or, probably more likely as the 3G networks come online, the cell companies are hoping that you will be getting your high-speed wireless at home through them.

This will be very interesting to keep an eye on.