No, but openness has a lot of advantages. It means that it's free, it's guaranteed to be supported by someone even if the founders all go away, you can trust it more since everyone can look at the source, and so on.
An you can't have pay for service like calls to 'real' phones because if the billing was done in the client you could simply remove it, forcing all the billing to be done at their servers - which makes it much more expensive.
An you can't have pay for service like calls to 'real' phones because if the billing was done in the client you could simply remove it, forcing all the billing to be done at their servers - which makes it much more expensive.
You mean like how land lines and cell phones do their billing on the provider's servers and don't do the billing in the phone itself because you could simply remove it?