Airport is pretty good at locating and finding WiFi signals to connect to but it can be poor at determining which one is strongest and by the time it has connected, the signal you wanted has gone.
WeFi automatically detects all WiFi access points within range and connects you to the one with the best Internet connection. If WeFi software detects a new access point, it allows you to be the first to map it. In addition to this, it also provides you with Instant-Messaging tools and a buddy list so you can see where your friends are currently connected.
The point of WeFi is that it's a community driven project that grows as people map it and add to the network. The more people that map access points and reveal them, the bigger the community becomes. This is all very well but the problem is that WiFi points come and go and there's no guaranteeing that the access point labelled on the WeFi map is for public use.
WeFi is a clever idea (although not original by any means) but it will only be of real use if significantly more people join it's network.