Well, the primary reason behind nobody using Ext3 like they should is that they need maximum compatibility with Windows, and it'll be a cold day in hell before Microsoft natively supports Ext2 or 3. Until they're either no longer the dominant game in town, or they start natively supporting Ext2/3, we're all stuck with Fat. I know a lot of companies would love to go to a free, open source file system, but so long as Redmond is king, that ain't happening anytime soon, as much as we'd like it to.