[germainebull]

What technology have you mustered to such an extent that you currently sell your knowledge?

[Fergal]

I work in automated software testing and use a tool called Ranorex. I don't sell my knowledge directly, but have qualified to become a Ranorex Certified Professional allowing me to gain employment using it and to use it to work on client accounts.

[oldbuddy]

I no longer sell my knowledge personally, but the programmer I sold my company to does. It involves point of sale software for auto dealers and the PC Hardware and Networking that goes with it. It fed my six kids quite well for over 20 years.