From this German-language article published in Austria, I had read that Internet-based telephony was gaining traction in Europe. The article was based on Bitkom’s information which they sourced from Eurostat which is the European Union’s statistics department.
IP telephony was found to be popular in the Baltic states like Lithuania but Germany was third behind the UK and France. Personally, I wouldn’t put it past France to take this technology up due to the VoIP services being part of their “n-box” triple-play Internet
Most setups were based around an existing handset that was connected to an analogue-telephony-adaptor or router with integrated IP telephony gateway. As well certain call classes such as international calls and calls to mobile phones do attract the VoIP users most likely due to cost savings.
But I notice a gap in the information about whether the customers use VoIP at home or at work. This includes whether multi-site workplaces implement VoIP for tie-lines and whether users are using VoIP without knowing it due to dial-plans that are set up for particular call classes.
It is also worth knowing whether most European users really make use of the PABX-style features like call transfer on their home VoIP setups. This is more so as manufacturers implement these features in ATAs, Internet telephones and similar devices.