In the past years there has been a discussion about the need of a network architecture like IMS.
Many detractors said that new telecom services only needed huge transmission pipes, but not the network intelligence of IMS.
In fact, current telecom services (like Skype for example) assume that there is only an anarchic “cloud” called “the Internet” which works on a best-effort basis, and so application developers have to deal with a non-predictable quality of service. This is the OTT philosophy (OTT stands for over-the-top).
OTT services are, for example, Skype or Internet Television.
Why do operators need IMS? Operators can aspire have the control over the business only if there is a kind of circuit-switched operation.
If there is not such circuit-switched architecture the business winners are content providers like Google.
This is why operators should push IMS since it is a packet-switched technology (the Internet we need) but at the same time allows build a service portfolio similar to the profitable circuit-switched world.