This article aims to address the use of hashtags in the digital social network of Instagram and its contribution to the algorithmic management of the platform. We investigated the hypothesis that the hashtag is an informative element that indexes and reinforces the meaning of publications and helps to track users on Instagram for mapping purposes and monetary gain by the platform and external systems. We are based on bibliographic research, in which we study the theory already published on this topic to understand the general process of capital accumulation in any socio-digital platform and the concept and use of hashtags. Hashtags complement the interactions carried out on the networks, in which users generate navigation and behavior data. We verified that the Instagram uses this data in its algorithmic treatment to optimize the distribution of contents in the profiles and its advertising targeting policy. We found that the contribution of the hashtag in this surveillance of networks is due to the fact that it is taken as information in the form of metadata that organizes and facilitates the tracking and mapping of users. To complement the bibliographic research we developed, we performed a query for a hashtag using an external system and found that, from the hashtags they use, people can be tracked not only within the Instagram platform but also outside it