Would it be possible to duplicate this anti-malware service without the involvement of Mozilla?  Could the code be obtained?  What about the malware list?  Are they open-source?  If they are, it seems to me that a company like Canonical could theoretically use the code in abrowser (or another browser that uses the Firefox code) and copy Mozilla's malware protection list on a slight delay.  You'd really just need someone to receive the malware list, decode the data, and resend it, presuming it is open-source and thus legal to do so.  If it's not, that's probably a reason to consider forking in and of itself.

Now, granted, there would be a lot of server and bandwidth costs associated with this, but I think that might be able to be mitigated by partnership.  If Ubuntu talks to Debian talks to Fedora talks to Novel and so forth, and they can agree on a common name and basic code-base for a Firefox clone, and to share expenses related to it, the costs can be split several ways amongst them.  A Windows port could even be created.  And all of this would create revenue to off-set the cost through a partnership with a search engine like Google similar to the one Mozilla has with Google (Maybe the partnership could even be with a different search engine like Yahoo that would bid higher to steal people away -- or a genuine open-source search engine could be created).  It would also create the all important name recognition where people would *want* to use the browser, and it wouldn't just be what they wind up using if they don't have the inclination to install Firefox.

One of the things that is probably key to a fork, if it's done, is that it not just be a half-hearted effort where someone throws up the firefox code with a name like "browser" and a generic logo, that's unique to just Ubuntu.  To be marketable, it ideally would have a cool name, good artwork, available across multiple distros and on Windows, and be backed by someone who can try to duplicate Mozilla's malware protection service.  Eventually, (down the road) maybe developers could even be hired and it could add distinctive features. 

Having said all that, I am rather attached to Firefox.  I think we all are.  But it's important that it be free as in freedom to be used on the distro.  Truth be told, I have a copy of Windows, and like using it -- and flash actually works correctly on it (Sorry gang, I'm sure flash works correctly on Linux for some people, I'm just not one of them).  The reason I dual-boot Ubuntu is because I believe in Ubuntu's principles.  I think a lot of folks feel that way.  If Ubuntu takes a direction where it's principles are no longer what they are, then it's only advantage is being free as in beer -- which is nice if you've lost you're Windows disks or know how to build your own computer, but most people have already paid for Windows and have a working copy.  One way Ubuntu sells itself is because it stands for something -- I think that's important.

I'm not saying fork or don't fork, I'm just saying principle should be considered in all this.  And that if a fork is made, it should a real attempt at a browser with a cool animal name and logo or something available on different distros and so on and so forth, etc..