Fedex Freight likes Linux. They’ve recently replaced NT/IIS with Red Hat 7.2/7.3 for their web frontend. From the NWFusion article:
Porting the Java-based applications used by the Web servers to make database calls to back-end systems was painless when the Linux swap was done, Boreni says. FedEx Freight loaded the Linux servers with a version of the Tomcat Java application server, which runs on top of Red Hat Linux. By installing the Tomcat application server, FedEx Freight was able to support the Java-based applications it had been running on the Windows Web servers – now replaced with Linux servers – without having to rewrite its applications. [via NewsForge]