Nothing groundbreaking but may be informative to some:
Understanding How Open Source Software Developers Make Moneyhttp://www.makeuseof...velopers-make-money/
"There are many myths about open source software (OSS) and perhaps the most common is this: open source and profit are mutually exclusive...The truth is: many OSS developers and projects do generate revenue. Some earn just enough money to survive while others produce so much money that they put proprietary alternatives to shame. How’s that for irony?"