In a case of exploitative business terms pursuant to Sec. 19(1) of the Act against Restraints of Competition the abuse of a market-dominant position does not always presuppose a causal relation between the market dominance and the condemned anti-competitive conduct (behavioural causality). A causal relation between the market dominance and the market outcome (causality of result) can suffice if, due to the particular market conditions, the conduct of the market-dominant firm leads to market results that could not have been expected in an environment of well-functioning competition, and in addition the conduct at issue not only represents an exploitation, but at the same time is capable of preventing competition. Such a causal relation between market dominance and market outcome can be given on two-sided platform markets in particular when the exploitation on the one market side on the part of the intermediary is simultaneously capable of impairing competition on the dominated market as well as on the opposite side of the market. If the market-dominant operator of a social network includes in its terms of use the condition that it will provide users with a "personalised experience" created using personal data of the user collected by registering the websites visited outside the social network, this can constitute an abuse of its market-dominant position.
