This study problematizes activity frames and participation frameworks (Goffman 1981), exploring how students deploy online (MSN Messenger) and offline activity frames in identity performances. One problem in analyzing participation frameworks and particularly notions of subordinate forms, like crossplay, byplay, and sideplay, is that these concepts require that the analyst can identify one dominant activity. This was not possible in the present data, which consist of video recordings of computer activities in a seventh-grade classroom. It is shown how MSN (online) identities were invoked in subsequent and intermittent face-to-face interaction; a dialogue that started on MSN would continue in face-to-face interaction, and vice versa. This means that frame switches constituted important features of the students' identity work. Similarly, the students employed nicknames or what are here called tags, that is, textual-visual displays of ‘speaker’ identities, located in the boundary zone between online and offline activities. In the classroom interactions, there was thus not one dominant activity frame, but rather the activities involved borderwork, and more specifically frame switches and a strategic use of tags.