Was reading "SIP: The Never-Ending Hype Wagon" . It says the people expectations vs actual.
"Today, H.323 commands about 80% of the international long distance VoIP minutes, which is an estimated 15.8% or 49.4B minutes of all international voice communication. Even Skype, perhaps the single-largest VoIP network, has not caught up with H.323 in terms of minutes of traffic. (Skype had 13.8B minutes of VoIP traffic in 2006 and held a 4.4% share of the international voice business.)
Where does this leave SIP? People are still working hard to try to make SIP a success story, even after trying for so many years and gaining so little market share. Standards bodies including the ITU SG11 and ETSI TISPAN are trying to position SIP as the NGN protocol and a replacement for the PSTN systems already deployed. But perhaps what is not so well understood in the industry is that the carriers are not likely to provide new, innovative services on top of SIP. What would be the financial motivator? Will users pay for new kinds of services and capabilities? What would those services and capabilities be? Can SIP provide them and would SIP be the right choice? So far, nothing new or innovative has been delivered and as financial reality sets in, you will likely see that little actually changes"
Read the article at : http://www.dailypayload.com/2007/0618.html
tailpiece: finally i understood, why SIP mag changed its name to unified communications mag. Reality strikes :-).