As posted by Frederik "Decaf" Holmqvist to the BeZilla LiveJournal Community (in the comments on that posting), the BeOS port of Mozilla now supports being set as your default browser - it supports opening links from applications such as BeShare, opening files off your disk with just a double click, and supports "Close All" from the Deskbar.

There are still apparently some bugs in the implementation, but its a major step towards being able to replace NetPositive with a newer browser that acts in a similar fashion.