But Sunday (first morning after daylight time change in USA), I looked
> at my phone and it was still an hour off. It wasn't until I made a web
> connection by asking it to check my account balance that the clock
> finally reset to correct time.
> So what the heck are all those little talks with the cell tower
> about if they don't even exchange the time of day while they are at
> it? (My definition of "useful" must be different than my
> cellphone's).
It depends on the cellphone and what technology it uses. If it was a CDMA phone the time is part of the spec so it will always be up-to-date.
GSM systems can and often do have a system called "NITZ" (Network Information Time Zone) which will automatically update the time and date. Not all operators use it and also not all handsets support the standard since it's an optional specification in GSM.