Firefox 2.x now alerts you to the availability of Firefox 3, however it is a siren song that can run you up against some sharp and IE style rocks in compatibility. Don’t upgrade until you understand these significant issues with Firefox 3.
You cannot easily run Firefox 2 and Firefox 3 at the same time, without significant and non-intuitive playing around with profiles. What are the Mozilla developers thinking? Web developers have to test their web pages with multiple browsers - who does not know this? What makes web developers howl about every new version of Internet Explorer? Let you users decide how many installations they want to run at one time.
Firefox 3 deactivates incompatible Firefox 2 compatible plug-ins, and does not offer any sort of emulation mode. This would be a non-issue if you could run Firefox 2 and Firefox 3 on the same computer without the hoop jumping. It was only after installing Firefox 3 that I discovered it deactivated the wonderful Addthis bookmarking tool. I use this tool many times a day because it allows me to not only bookmark pages using DIGG, Google Bookmarks and other services, but also to easily link a page to my Twitter profile. Nothing Firefox 3 adds replaces this, and its more important to me than the upgrade.
Why didn’t I visit the Mozilla user other community forums first? Because this is my first disappointment with Mozilla.
As of this date, the forums are packed with unhappy upgraders looking to downgrade to Firefox 2. If you are considering upgrading - read the firefox forums first.



