PC will be the new (mobile) phone

"WHAT? Are you crazy? What a preposterous title?
If anything, the mobile phone will be the new PC!"

This is the reaction I am expecting to hear. Ok, bear with me for a moment:
- An Internet-connected PC is able to make calls through VoIP technology, right?
- At work everyone uses a PC, right?
- Connections are getting broader and cheaper by the minute, right?
- Laptops are getting cheaper and lighter, by the minute, right?
- Most computers have WiFi capability, right?
- Companies in general are cutting costs, right?

So add all these things together, and the bulk of business calls will be done on Skype or similar software. Operators are trembling (well, they have been for some time now), or else they are living in denial. The bulk of their revenue is indeed coming from business customers, which have an ARPU at least twice as higher than private customers. Operators are changing to advertising-based revenue instead of subscription-based revenue for private customers, but it is not feasible to do it for business customers.
So even this gold mine is drying up? Oh yeah, baby!

So you have people getting used to call through their PCs the whole day because it is cheaper--and they know it.
Will they change that when they get home? Unlikely!
For private use, PCs have other benefits too. BIG screens. Let's face it: the mobile phones nowadays are stupendous (I would say they are photo/videocameras capable of making calls), but they are small. And after all, even if in short term they will come with a monthly usage flat rate, you cannot really use it to watch movies. You can see them, but you cannot watch them. You can and use it as an MP3 player. And you can play some online games, but isn't it much better on a 19" screen and a proper keyboard/control gear? Of course it is; just like a movie on a cinema or on a TV screen.

The other advantage is that advertisers can indeed track your profile through your mobile phone usage much better than through your PC usage, no matter the number of cookies and spyware they use. For instance, I keep receiving annoying pop-ups of a cola company when accessing a social network platform, when everyone knows I hate them (the cola... well, the platform is a necessary evil, mind you, I do prefer Yahoo!Messenger).
Thus they have been paying big euros for me to...
spread negative buzz! Brilliant!
In truth, advertisers can indeed send you meaningful SMS with advertising, but cannot do it as easily on the Internet (I did write "meaningful"), unless they have some sort of contract with the page you are visiting--the best example is the search engine--and even that has a factor of "wishful thinking".
All the rest seems like "interruptive marketing", even if it relates to the page you're accessing--because if it does not relate, it is just a big waste of money for the advertiser and nuisance to you (AKA spam which is effectively automatically filtered on Yahoo!Mail).
So if you want to keep a little bit of privacy...
use the Internet (at least, for now).

Of course, a laptop doesn't fit in your pocket--and not everyone is connected on Skype 24 hours a day. That's the advantage of the mobile... multimedia communication device--so you can beep the other person to log in into their account.