Definition of Commercial Open Source Software (COSS) business models is good background reading:
So what’s the right OMTM in the early day of your product development?
I propose: Time-to-value
“Time” here is straight forward – lower the better.
“Value” needs precise, rigorous definition that is technology and problem specific. Your distributed database is valuable because it can serve data with no down time when servers fail. Your continuous integration tool is valuable because it enables application developers to push improvements faster without breaking the application itself. You get the idea.
This OMTM is from Lean Analytics.