During the last couple of decades, a growing body of research has provided insights into the complex processes of learning that take place in museums. Interestingly, museum-related learning is not limited to the actual visit: what takes place before and afterwards has a profound effect on the learning outcome. The study presented in this paper focuses on the post-visit aspects of the learning process. Previous research shows that visitors make connections between their experiences in the museum and experiences that happen after the visit. Sometimes these connections can occur weeks or months (or even years) after the visit, depending on when the visitor happens upon a situation that allows the connection to be made. Documenting these events is obviously quite difficult. Even though it is possible to re-establish contact with visitors after a few weeks or months (e.g., through telephone or e-mail), the information obtained is not in situ. The goal of the present study is to attempt to acquire and analyze more data from these in situ situations, and to re-present the data in an exhibition. To this end, we have designed a system that allows visitors to send images and text messages to a central server through e-mail, SMS or MMS. The data from the server can then be visualized as a weblog (blog) or in some other suitable form. We collaborated with the Museum of Science and Technology in Stockholm, Sweden. A large part of the Museum's Science Centre is devoted to five mechanical principles: the screw, the plane slope, the lever, the wheel and the wedge. We have designed an exhibit that utilizes our system to present messages (images and text) from visitors on the subject of the five principles in the science centre itself. It is also possible to access the messages through a public Web page. From the Museum's perspective, our exhibit not only provides new opportunities for documenting post-visit learning processes, but also has the potential to provide new forms of evaluation data that might be difficult to obtain through other means. Furthermore, it allows Museum visitors to extend the original scope of the mechanical principles exhibition by allowing them to provide their own content (and reflections upon the existing content), a re-occurring theme in many recent technology-based exhibits. The paper provides a description of our system, the exhibit we have built, how the exhibit is managed, and how it has worked in practice.