I use it to keep my personal and business voice and text lives separate, but with one device, the iPhone. When I switch jobs, my personal number never changes and friends and family are none the wiser. Additionally I've avoided costly cell plans having a iPhone that is not activated but fully functional as a phone via WiFi using Skype & GV. While in between work I can use a cheap plan (now Virgin's $25/month) to maintain coverage and again, same number.

I was hoping this would be a bit more functional than the HTML5 version, but so far, not really.