Digital markers such as barcodes and QR codes are ubiquitous. However, these codes are normally used only for retrieving a small amount of information, such as a product identifier or a web link. Much previous work has investigated the value of associating digital content with physical objects in everyday scenarios, but has so far relied primarily on adding new markers to existing items, or studied only short-term usage. In this paper, we explore the benefits of "commandeering" existing object labels to support this interaction. We add a social layer to existing digital codes, allowing users to "tag" any marker in their environment with their own messages, which can then be viewed by any other user. The core contribution of this work is the findings and insights that were collected in user studies. We explored the use of our design via two deployments that demonstrate the potential of such a system beyond its playful starting point. We conclude the work by drawing out a number of key design elements for future appropriation designs.