Participatory design (PD) is mostly conducted face-to-face with the support of physical props. Although this is a valid and very beneficial approach, it is unfortunately not applicable in every project context. It is especially challenging when a project's stakeholders are widely distributed; software tools can address this challenge. A review of existing online annotation tools indicates that they do not meet the essential requirements for distributed PD tools. To address this issue, a prototype called Pdot has been developed and evaluated with some users whose feedback will inform its future development.