Note: These are rough notes from the WWW2007 conference.
There is such a diversity of devices. Some people want big phones and some people want small phones.
If you really want to tailor an experience, you need to know a lot about that device. Funny that the biggest money is selling wallpaper and ringtones to teenagers.
All the device characteristics communities now are focusing on ways to give APIs to get information on device information. There are three groups that are working on this: W3C MWI DDWG, OMA, and W3C UWA DCCI.
They are also building an ontology so that the different APIs will talk the same way. They are looking for people to contribute characteristics needed in the ontology.