"Sender-keeps-all" or "bill-and-keep" accounting mechanisms are simple accounting schemes common in the deployment of new telecommunication technologies. However, in asymmetric traffic environments or where highly diversified service offerings emerge (e.g. those requiring guaranteed bandwidth), these models tend to shift to revenue sharing mechanisms among operators and/or content providers. In some cases, this can lead to new market dynamics. One example is the success of NTT Docomo's i-mode service, which some argue is mostly related to its billing gateway technology, permitting revenue sharing and encouraging the growth of new external content providers.
Many previously "free" Internet services are shifting to subscription or metered-based schemes and there's a lot of standards activity underway focused on charging, accounting and cross-operator settlement schemes for IP-based networks. In the public switched telephone network (PSTN) world, which is focused on a single service, voice, accounting mechanisms are primarily built around call detail records (CDRs). In the IP-based world, the service offerings can be much wider (voice, email, web, streaming access), so the challenge has been to develop a more flexible format that can capture the relevant metrics for a wide range of service classes. An interesting development is the Internet Protocol Detail Record (IPDR).
ITU-T Study Group 3, who deal with tariff and accounting principles including related telecommunication economic and policy issues, are currently meeting at the ITU. At this meeting, the Internet Protocol Detail Record Organization (IPDR), has given an interesting presentation (PDF) on its latest activities, particularly with regard to the emerging Network Data Management Usage (NDM-U) specification. This is a development to keep an eye on in the future.