What is a linear workflow and how is it done in Fusion?

I'm a newbie and I hear a lot of people talking about linear workflows but i'm not sure what it is, why it is important and how it is done in Fusion.

I think it is something to do with colour spaces and gamma curves?

Could someone explain to me what it is and how to do it, or direct me to a good source? I've came across the term linear and gamma a few times in books etc. but I haven't quite understood it yet.

a good article about it from stephan ihringer:
http://www.comp-fu.com/2012/03/linear-g ... on-part-2/

and a good series about linear light workflow (is about nuke, but will give you a understanding what is that all about):

Thank you, very much appreciated.