There are so many applications that you can add to cell phones to allow for some form of calling. For the life of me, I can't figure out how these would be mainstream - and how there could be a demand for hundreds of them.

Are people now trading in all of their calling cards for an app? All the penny pinchers that were using calling cards have a data plan on their phone that allows them to make VoIP calls?

I get that landline usage is way down as folks move to not only cellular only, but pre-paid cellular. But how much International dialing is being done on cell phones? Wouldn't the majority be migrating to Skype?

Even look at that market: the PC-to-PSTN market. Pulver's FWD was in the marketplace first (and won an FCC ruling with his name on it). Yet it seems that only Skype is left.

Leads me to think that when these mobile VoIP apps are being marketed, you need to be very specific about what the benefit is. And you need to make it stupid easy.