The Power of Unreasonable People

One of our reading assignments for this week was to read the first chapter of "The power of unreasonable people," by John Elkington and Pamela Hartigan. This chapter dealt with defining three different types of social businesses: the non-profit, the hybrid, and the for-profit social business. On the whole I felt this was a good explanation of these three different business models (although I felt they kept pushing the term "unreasonable," I guess in an effort to justify their title;)

One question that I still have, though is where the line is drawn between the hybrid model and the for-profit model. It seems as though in the examples they gave, the hybrid models were both earning modest profits, but that they were investing the profits back into their companies and expanding their growth. Is this not what is generally done in a for-profit business model too? Or is it a question of how much profit is being made, and whether efforts are being made to maximize that profit?