Skype differs from other VoIP-systems by several factors:
Skype is very popular. During the first week in August of 2003, more than 60 thousand people downloaded the Skype-client. Today, Skype is available for the following operating systems: MS Windows, MacOS, IoS, PocketPC, Android and Linux.
Now with "NuovoVoip" by TelefonicaWeb.net ,you can call with internet telephony rates from any landline or mobile, without having to use internet, 3 g, wifi, etc