I've used this program since 2000. I tried to set it up for a customer to use as inter-office chat but now they require a text to a cell phone to validate a new account. It used to require only an email address which I thought was reasonable.
No way an I sending 5 mobile numbers to Russia - The hacking capitol of the world!
http://time.com/*******/the-worlds-5-cybercrime-hotspots/