Most often, I found the US government and its agencies quite Microsoft friendly. Wanna have an example ? Here is the latest one.
The Copyright Office invited comments on an upcoming Web service for prospective copyright owners that may launch with support for Microsoft Internet Explorer only.
“(…) At this point in the process of developing the Copyright Office’s system for online preregistration, it is not entirely clear whether the system will be compatible with Web browsers other than Microsoft Internet Explorer versions 5.1 and higher (…)”
Should this be accepted, this means that people will need a Windows-based PC and IE to preregister copyrighted material in the future.