During the recent Syria Internet blackout, rebels within the country used Skype to communicate with one another, and was used alongside stockpiled equipment and a satellite connection in order to communicate.
They were able to communicate not only with other rebels within Syria, but internationally, too - all despite the government trying everything to stop them. The New York Times reports of how the rebels would tell other groups of military movement, with equipment being smuggled into the country being the savior to the rebels during the blackout of Internet access.
There was an alleged video chat session with rebels, who used a laptop and four battery backups and a generator - other equipment was also used during the time that the Internet was down. Fast forward to today, and the Internet is mostly restored to the country.
It has been alleged that the Free Syrian Army who fights against the Syrian government have all but switched Skype, turning away from the usual phone lines and cellphones.