I'm curious about how .NET will affect Python and Ruby applications. 
Will applications written in IronPython/IronRuby be so specific to the .NET environment, that they will essentially become platform specific? 
If they don't use any of the .NET features, then what is the advantage of IronPython/IronRuby over their non .NET counterparts?
IronPython/IronRuby are built to work on the .net virtual machine, so they are as you say essentially platform specific. 
Apparently they are compatible with Python and Ruby as long as you don't use any of the .net framework in your programs.
How will Python and Ruby applications be affected by .NET?