I like caller tunes (or hello tunes) as much as I like powder coated metallic blue hand cuffs.
1. Poor Feedback - The earlier tones give clear feedback about the state of the call. In caller tunes, the caller does not get any feedback. They don't know if the called phone is ringing or busy. The result is quick and multiple hangups by callers.
2. Mental Model Mismatch - The caller expects a familiar ring or a busy ring. Any other type of ring is a surprise and frustration.
Mobile companies' revenues may go up. There are two reasons:
a. More missed calls to the called number as callers hang up in surprise. The called person then rings back the "familiar" numbers thereby increasing the mobile company's revenues.
b. Revenues from caller tunes feature subscription.
Mobile companies' revenues may also go down due to lost revenues in calls that never connected.
There may be a user population that will use this feature - there is enough literature available on gift giving behavior among young adults. However, I have not seen any ethnographic studies or usability tests published on this. Any links?
Age-old practices in the ‘New World’: A study of gift-giving between teenage mobile phone users
by Alex Taylor and Richard Harper presented at CHI 2002
The Gift of the gab?: a design orientated sociology of young people's use of "mobilZe!"
by Alexander Taylor and Richard Harper Journal of Computer Supported Cooperative Work (CSCW) 12(3), 267-296