At the risk of appearing a skeptic, I still do not find that the hosted PBX market is markedly bigger, in terms of revenue opportunity, than the older “Centrex” services cloud telephony replaces. Neither, apparently, does Solgari, which sells cloud telephony to business customers globally. But Solgari also expects an inflection point to occur within the next three years.
The global market for Hosted PBX services is still small with penetration averaging between 4% and 7% in the largest SMB cloud services markets, according to Solgari, a supplier of hosted PBX or “cloud telephony” services.
Solgari of course hopes, and expects this situation will change in the future. So far, though, adoption remains in single digits in most markets where Solgari operates, it appears.
In the U.S. market, around 500,000 small and medium-sized businesses currently use a hosted PBX service, representing an $800 million in annual revenue, Solgari argues. The hope or expectation is that a majority of premises-based phone users will ultimately switch to hosted services.
That would be a big change, indeed. About half of U.S. SMBs use a PBX, but only seven percent have a hosted or virtual service. Among larger SMBs, PBX adoption is especially widespread, but the use of Hosted PBX services is still very low, Solgari says. 
source: Parallels
In the United Kingdom, hosted PBX services now represent just four percent penetration across all SMBs. Within the SMB market, 10 percent of very-small and 38 percent of small SMBs are currently using in-house PBX systems.
Of these, 24 percent of the very-small SMBs and 43 percent of the small SMBs are considering adopting hosted PBX in the next three years.In the Netherlands, the hosted PBX market represents four percent penetration among SMBs. Of surveyed SMBs using in-house PBX systems, up to 40 percent are considering adopting hosted PBX in the next three years.
The hosted PBX market in France also has about four percent hosted PBX penetration. As many as 40 percent of SMBs are currently using PBX systems and of these 32 percent are planning to adopt hosted PBX within three years.
The Spanish market also features four percent penetration.
Among Polish SMBs, hosted PBX penetration is three percent. Among SMBs that currently use PBX systems, though, over 50 percent are considering adopting hosted PBX in the next three years.
Within the Australian market there is currently only two percent penetration of hosted PBX services. Some 65 percent of SMBs are using in-house PBX systems. Of these, 37 percent are considering adopting hosted PBX systems. At least as Solari sees the market, the next three years are crucial, and shoul see an inflection point in hosted PBX adoption.
Inflection points are important. What surprises some of us is that the inflection point for hosted PBX services has not already occurred.
