Gamasutra - The Hidden Evil Of The Microtransaction.
The problem with all this is this it is an ambiguous, gray area. The real kicker is that gray areas are always green-lit by greed. In the interest of a 'little more', so much wrong has been done. So many ideas ruined, communities broken, and teams overstretched by wanting that little bit more. The old sustainable farming arguments come into play here.

The massive problem is that you as the Games Designer or other development members do not always have the final say, but you can still fight your corner. You can build your arguments and try to provide some strong research and data to help your money people see the long term view.