Skype is a relatively new entry into the world of IP-based communications. It provides free phone and chat capabilities between computers running Skype, and allows you to make calls or send text to ordinary phones and cellphones for a modest fee.
Check out this image from the Skype online help pages explaining how to use Skype to send SMS messages to cell phones:
The last name on the list? Stephen Harper.
I know it's just a coincidence. I doubt Stephen Harper gives out his cellphone number to just anyone. In any case, I can't see him on a list along with Jeff Clarke, "average homeboy", and Joseph Allen, "musiq souldchild". But then, who knows? I bet he plays the air guitar like everyone else when he thinks no one is looking.