Self observation: It's interesting how even little things can have a big impact on usability and behavior. When I am in public places and use an unencrypted public Wi-Fi hotspot I want to be as secure as using a 3G connection with proper authentication and encryption enabled. So I use a VPN. However, I manually have to activate it and even though it's only 3 clicks I don't really like to do it. So I am sure if I had a 3G card inside my netbook instead of an external 3G USB dongle I would just not bother with the Wi-Fi and VPN and just get connected over 3G, despite a Wi-Fi hotspot being available. So if Wi-Fi is to become a way to offload traffic from the 3G macro network then a piece of software needs to be available that checks which options there are to connect, selects 3G or Wi-Fi without user interaction and in case of Wi-Fi automatically establishes a secure and encrypted tunnel. Without user interaction, though, that's the important point!