•An explanatory model of individual social networks capitalization is proposed.•Lin’s model on inequality on social capital is contrasted and complemented based on ample social data.•We contrast the determinant variables on social mobilization of resources.•The diverse expressions of goal oriented individual social capital mobilization are analyzed. The objective of the present paper is to characterize the structure of individual social networks and to provide new insights into the underlying mechanism of individual social capitalization process. In particular, we put to the test three main assumptions underlying Lin’s seminal explanatory model of individual social capital determinants (Lin, 2001). We analyzed the results of an extensive and specifically designed survey on personal networks in Spanish society (OSIM, 2011). Our findings, based on the use of Principal Component Analysis (PCA), regression and structural methods allow us to complement Lin’s general model distinguishing accessibility and mobilization of social resources. Furthermore, the empirical evidence suggests the need for introducing a significant distinction between instrumental-expert and expressive mobilization. Finally, our analysis allows us to identify the main determining factors of both forms of capitalization of personal relations.