The "Wi-Fi Browser" is a direct to the web connection via the wifi network. The "Internet Browser" is a connection to the carrier's Infrastrucure via the wifi network, Internet and RIM's infrastructure. The "BlackBerry Browser" is a connection to the BES via the wifi network, Internet and RIM's infrastructure. All 3 browsers use the wifi network for higher-speed data transmission, but the latter 2 are compressed and optimized for the BB.

Additionally, if you set up a bookmark to use the Wi-Fi Browser, it will not work when not connected to a Wi-Fi network. But if a bookmark is set to use the Internet or BB broswer, it will work when not connected to wifi, because it will use the edge connection. A Internet or BB browser bookmark will also work with wifi, but faster compared to edge.