Prior to the web, social assets like individuals’ reputation were stored in the collective memory of the communities they belonged to. As people within a community listen to your jokes, they begin to seek out your company more, and word gets around that you’re funny. However, if you were to move to a different place, your reputation would not come with you. Online, as reputation can now be measured in the form of social gestures, we have a way of making it explicit, publicly recorded, and therefore available more globally, albeit in different ways.
Trust becomes disembedded, fungible, abstracted. But this seems to alter the fundamentally local nature of trust as traditionally understood, opening up the concept to various subversive strategies, to possibilities of manufacturing a sort of ersatz trust that is rooted in captured online gestures but has no basis in community interaction or sustained commitment to a group's well-being. That is, it reduces the broader notion of trust (which has to do with community values being sustained) to reputation (which has to do with strictly personal goals and tactics for achieving them).
Social currency -- the term the author is using for these captured social gestures -- is a bit of a misnomer since it posits individuals who participate in collective behavior only to augment their strictly personal reputation. Individual identity is rigorously maintained in the face of groups that form, militating against the possibility of group identity or group responsibility. Basically social currency is a euphemism for personal branding, exploiting social interactions to build personal brand equity under the assumption that all social interactions are governed by a consumerist ideology and take a market-like form. In other words, when ever we have a social encounter, we meet as traders looking for a profitable exchange to enhance our brand value. The purpose of social encounters is strictly for exchange and not for any ephemeral or misconstrued pleasures that supposedly come from uninstrumentalized company-keeping.
Obviously social media encourage this kind of reputational accounting. It makes them the central banks of the new "social currency," the management of which puts them at the heart of social exchange. This allows them to broker attention (selling ads to third parties which can be interjected as the social media companies oversee social exchanges) as well as theoretically collect interchange fees for guaranteeing trust between parties. But the quantification of reputation in social media also encourages us to regard building trust as the goal of behavior rather than its by-product, a condition that upends the standard logic of social behavior. It allows trust to stand independent of relationships and casts social relations into the form of a game we play to further exogenous goals. (We have "friendships" to enhance trust scores; friendship in itself becomes apparently worthless if it's not improving our metrics.)
Reputation-measuring systems are a mode of social deskilling. Social media companies has an incentive to erode our natural skills of etiquette and social navigation so that we become more reliant on the companies to manage our awkwardness for us.