Though we can probably safely assume that anybody using a Voip program in the first place is at least a -bit- computer literate, and willing to try something new.
For the technicalphabetic people an unknowm piece of 'tech' is 'new' and a new program just a different way of expierencing 'old tech' and are therefore unwilling to learn.
It's sad as hell... in the 21st century one would expect people to know how to operate GUI desktop computers now that we al depend on them, but no...
People need a drivers license to learn about computers. The EU demands it, but did it the, *sigh*, 'Microsoft products equals computers' and you learn nothing else than where to click on the screen... *double sigh*.