I can't check now because I don't have access to my PC (am using a Mac) but there is a piece of software called http://www.bikechecker.com which shows all this kind of stuff. I was pretty sure that the Orange Five has a falling rate, i.e. the amount of wheel travel increases for the same amount of shock shaft travel the further into the travel you go. It's the exact opposite of what most other bikes have (progressive rate, i.e. the shock gets harder to compress the further into its travel it goes).
It gets confusing because the terms can be counterintuitive, i.e. progressive rate means lower values of leverage ratio so for example starting at 3" of wheel travel to 1" of shaft travel, then falling to 2" of wheel travel to 1" of shaft travel. Thus the force needed to compress the shock for a given movement in the wheel needs to increase.
See below taken from the bikechecker website. It only runs on a PC but it's fun in a geeky kind of way.
Progressivity – used in two ways – in a geometrical sense and regarding forces. Geometrical progressivity describes the changing of the leverage ratio throughout the travel. A progressive rate suspension means lower values of the leverage ratio for larger travel. A falling rate suspension is the opposite. A linear rate suspension keeps a constant leverage ratio. These affect the “feel” of the suspension. If we take forces into the account as well, we talk about the “real” progressiveness of the suspension. This represents the changing of the rate between the force needed to compress the suspension to a specific travel position, and the balancing force performed by the shock. Thus, a progressive suspension “stiffens up” at larger travel positions, while a falling rate suspension feels really plush and is easier to bottom out. Bike designers tune their suspension for the desired behavior. Short travel cross-country bikes usually use a progressive setup, while downhill bikes usually use a more linear setup to be able to absorb repeated larger bumps. For “freeride” bikes, a progressive setup is optimal at the end of travel to prevent harsh bottom outs on big jumps.