A Linear workflow (LWF) exploits the fact that your renderer works internally in float (linear) space. It generates data that 8-bit output clips away, as it is gamma encoded for monitor display. What a shame. That data is very useful in your post-production compositing and color adjusts.

Major issues to work in LWF:

• Physical accuracy.
• Realistic lighting
• Greater adjustability in post

Additional info:
http://www.creativecrash.com/tutorials/linear-workflow-in-3dsmax-and-vray
http://www.fxguide.com/modules.php?name=fxpodcast&pa=listen&path=modules...
http://www.poynton.com/PDFs/GammaFAQ.pdf