I upgraded from Debian Etch to Sid today and part of the upgrade included the transition from Firefox to Iceweasel.  Iceweasel is a re-branded version of Firefox to get around trademark issues.  The only functional difference I can see is that all of the built-in update features are disabled in favor of Debian’s packaging system.

I just pray no one notices because I really don’t want to have to explain why my browser, which looks like the beloved Firefox, says Iceweasel at the top.  Its just silly and embarrassing.