In this essay, I introduce the figure of the “neoliberal subject of value” to explore the affective ambiguities of what Tiziana Terranova has termed “free labor,” or the voluntary, unwaged, and exploited activities that generate the digital data, content, and connections central to informational capitalism. If, as Terranova argues, free labor is characterized by exhaustion—due to the lack of means by which this labor can sustain itself—why are millions of people still sustaining a commitment to such pervasive modes of unremunerated work? To formulate an answer to this question, I first turn to the neoliberal theory of human capital, which offers a more fruitful avenue for the analysis of digitally mediated “living labor” than the Autonomist Marxist theory that inspired Terranova’s analysis, by elucidating how a logic based on competition, entrepreneurialism, and speculation has transformed how work is understood and valued. Second, I discuss the central role of commensuration within capitalist value production, arguing that human capital functions as a “commensurating machine” that allows neoliberal governmentality to permeate areas of life previously impervious to market rationality. Third, I show how such practices of market commensuration depend on a range of evaluative devices that create environments of equivalence and hierarchical difference, explicating how these devices have come to play an increasingly important role in contemporary digital culture. I then discuss a case study of Klout, a digital device that commensurates variegated social data into a score that ranks users according to their “influence,” which has become an important, if contentious, measure of human capital in information economies. Finally, I return to the neoliberal subject of value and her affective ambiguities, which index both the aspirations and exhaustion of competitive value-generating sociality.