Win32 Fibers are mentioned on several WikiPage''''''s (ThreadsConsideredHarmful, MessagingAsAlternativeToMultiThreading, MultiThreadedGuiWouldBeGreat, WriteYourOwnThreadingPackage) where they are described as non-preemptive threads, i.e. they have to be manually scheduled by the application.

Are fibers the same as coroutines (see ContinuationsAndCoroutines)?

See http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dllproc/base/fibers.asp?frame=true for more information about Win32 fibers.