Recent approaches to the study of identity in online contexts underline how people on the Internet have multiple identities and are at risk of identity fragmentation. Subjectivities are context-specific, negotiated with other people and actualized in Self Presentations. The aim of this study is to investigate how social media users deal with choices regarding their Self Presentation and how different profiles of the same person relate to one other. Thirty-six users with accounts on two blog-hosting services and one social network website answered an online structured interview and elaborated on the different choices of Self Presentation for each service. Content Results show users accurately and consciously choose the way they present their Self according to their aims, actual and potential readership, and the technical possibilities of the media. Answers also show that people online are conscious of the multiple presentations they enact, and they feel an underlining sense of unity and coherence, which may be traced back to the concept of Self.