Some people may want to monetize faster, but the key is to figure out what is the right speed of monetization. If you act too aggressively, there is a real risk you will lose the huge active user base.
Implicit in this statement is the recognition that Skype needs to make more money off its users, faster. Quite a trick for a free phone service. But still, not moving too fast? It's been four years and Skype has 220 million users! Would Zennstrom wait until Skype has half a billion users? A billion?
The risk of losing users because of increased or new fees doesn't decrease over time. On the contrary; users become more and more used to services being free. Attracted by free services, they come to expect it, and chafe at being charged. Acting as if their is some far off date when increased fees are suddenly more palatable belies the fact that Skype doesn't know how, or is afraid, to turn their service into a real moneymaker.