Social capital is becoming increasingly important in the knowledge society. Most studies of the phenomena that are considered as social capital have, in the tradition of Robert Putnam's writings mainly focused on what can be called social capital in civil society in the real world - outside the virtual world, i.e. the Internet community. This paper tries to clarify the significance of trust as the element of social capital that relates ethics of the Internet community to theoretical and empirical approaches. Results indicate that studies on trust related to the Internet can be positioned in two dimensions -- ``studies on the system trust (especially, trust in the system infrastructure) -- studies on the personality trust'' and ``studies with risk management approach -- studies with trust management approach.'' Generalized trust has significant relationships with reciprocity, human interaction and cooperation on the Internet. However ethics does not simply correlate with trust.