pc to pc and back in the late 90's or early 2000's.
Isn't Ubivia wi-fi or internet based (rather they use data plan or wi-fi)... like VRS or IR-relay or AIM? if so, same difference.. and from what I understand, ICQ is part of AOL , which is probably why people are seeing the same method through AIM.
although, with aim or icq, you can't really have your own number like VRS or ip-relay, nor these IM service provide a relay service for hearing people to contact you. IP-relay or VRS will use AIM to reach you, though. you have to leave it on in case someone want to contact you.
If you can provide relay service (or get relay service to give people an option to use your product instead of aim), and a way to alert people better.. I think people maybe more interested in using it instead of aim.