Verizon has been very open about its pursuit of Voice over LTE (VoLTE) as a high-tech replacement for traditional circuit-switched voice, competing test calls way back in early 2011 using the LG Revolution. At that time, the company had said that the service would be commercially available in 2012 — and that very well might still be true: an analyst with Northland Capital Markets is claiming that the company already has two trial VoLTE markets turned on, with a national rollout planned for 2013. As Light Reading notes, that doesn't necessarily preclude an initial commercial rollout this year since Verizon would probably be looking to deploy the service market by market, and 2013 nationwide availability lines up with the carrier's plans to overlay its entire 3G network with LTE next year.
The technology is important to the industry for a number of reasons, chiefly the fact that LTE is an entirely IP-based technology — in other words, there is no way to deploy legacy calling services on LTE without falling back to CDMA or GSM, so only by using VoLTE will carriers ultimately be able to eliminate 2G and 3G networks and refarm spectrum. That's not something that'll happen any time soon, but it'll eventually have to happen nonetheless.