In a startup company, its common for certain employees to be compensated with some form of equity. When you incorporate, you would adopt a stock option plan and then issue options to the corporation’s employees to compensate them for their past services and to incentivize them to stay and keep up the hard work – make sure you vest!
With LLCs becoming ever more common, the owners of a startup organized as an LLC want to be able to compensate and motivate their employees and contractors in the same manner. They can do so by granting employees LLC profits interests.