While clients all over the world are lining up to buy iPhones, the next big hit make come from Google, in the form of Android. The iPhone is a tightly controlled platform whereas the Android platform is open. This difference may be deemed too geeky to make a difference. I beg to differ.
When people realize that they can make VoIP calls using nearby WiFi networks for free, or VoIP-to-PSTN calls for 20th of the current price, they'll go berserk.
There are two ingredients missing for this scenario to become reality. First, there must be an Android phone that people can buy off the shelf. Second, people need to start sharing their WiFi networks. This is not happening, or nearly not fast enough. Our minds are imprisoned by the notion that bits are scarce. Bob Frankston argues why this is the case but should not be.