Existing web-content adaptation engines assume that the task being undertaken is the browsing of the web-pages by a single-user. There are, however, other tasks that necessitate the viewing of web-pages on mobile devices. One such task, which forms the motivation for this paper, is mobile web-based collaboration involving the co-browsing of web-pages from multiple devices. The paper begins by reviewing the considerations taken into account by existing web-content adaptation engines in handling the single-user browsing task. Next, the differences between single-user browsing and co-browsing are discussed and a content adaptation framework proposed based on the concept of shared viewpoint and personal viewpoint. Finally, the effectiveness of the framework is demonstrated through a perceptual experiment.