How has the diffusion of online communities changed howtheir users construct, view, and define their identity? In thispaper, we choose to approach this issue by considering twoparticular philosophical problems related to personal identity:1) The Characterization Question, namely “which actions, ex-periences, beliefs, values, desires, character traits, and so oncan we attribute to a given person?” 2) “How do self-other re-lations affect the ethical implication of identity construction?”To address them, we adopt a comprehensive framework com-posed of cognitive niches and cognitive niche construction the-ories, and we discuss different philosophical and technologicalnotions. In particular: the Filter Bubble problem, the conceptof affordances, and the Sartrean idea of Bad Faith.