And Illich (where the term "tool" is quite broad, including anything from a knife to a highway system):

Tools foster conviviality to the extent to which they can be easily used, by anybody, as often or as seldom as desired, for the accomplishment of a purpose chosen by the user. The use of such tools by one person does not restrain another from using them equally. They do not require previous certification of the user. Their existence does not impose any obligation to use them. They allow the user to express his meaning in action.

Industrial tools deny this possibility to those who use them and they allow their designers to determine the meaning and expectations of others. Most tools today cannot be used in a convivial fashion.

Damn, thank you! I often refers to myself saying "Naive heuristic : avoiding gadgets or services (free or not) that increase inequality by design, through technology or business model or both, would be a good starting point." but I can now point to this!