Many will say yes, I suspect, referring to things like:
- WiFi, muniwifi, WiMAX, xMax, 3G
- IMS, A-IMS
- Roaming: T-Mobile, Boingo, The Cloud
- Sharing: FON, Free
- Dual-mode handsets (cellular/WiFi), WiFi handsets (like Sony's Mylo).
- Clients/services: Skype for Mobile, iSkoot, Cicero, Truphone, Nimbuzz, Jajah.
Of course, there are similarities between fixed and mobile VoIP:
- VoIP needs an always-on BB connection (but not strictly, see KPN's Slim or VoxLib).
- Traditional voice revenues are at risk.
- VoIP delivers cost savings and potentially better voice quality.
- Free on-net and cheap off-net calls.
I believe there are some major differences between the mobile and fixed worlds, even if they can be dealt with:
- Wireless licenses and spectrum are scarce. Perhaps less so when analogue TV spectrum becomes available. Also, when operators like 3 and Xfera enter the market, not te mention WiMAX and xMax.
- VoIP blocking: there is no net neutrality debate in wireless (yet). T-Mobile however backtracked.
- People use their handset differently from how they use a PC. Demand for things like mobile internet and mobile TV is unproven/low. Downloading clients is more of a hassle. Not when they come pre-installed.
- Fixed BB is cheap because of competition, most notably infrastructure-based competition. There is no such thing in the wireless space.
Continuing on the last point, it would be my understanding that mobile operators have a chance of defusing the wVoIP threat slowly. They can make an offer to their customers saying: ditch your voice bill and take this data subscription! As long as it is priced at around the present ARPU for voice (+ messaging) + data.
PTTs have done this before, when there was no such thing as BB: rebalancing tariffs away from per-minute charges and toward monthly bills. The differences between mobile and fixed makes it harder for them to rebalance the VoIP-threat away than it should be for wireless operators.