Well, it’s definitely still a thing!  VoIP, or Voice Over Internet Protocol, is exactly what it sounds like: the use of internet infrastructure to transmit voice over the internet.  Instead of the phone connecting to the telephone network, it just connects to the internet, and routes the voice signal over that network.
assistant
Are you talking about internet-based telephone services? In which case I think things like Vonage and Comcast have recently been changing the structure of their service to use VOIP exclusively.
assistant
I was thinking about getting rid of my landline phone and going with VOIP or something like that for my home telephone service. Is that still a thing or is it still viable to use?
user