Information is displayed on a device by writing data to a buffer in memory, the content of the buffer describing a screen display of the device at a particular point in time. A watermarked version of the buffer content is generated by watermarking the content of the buffer with data, such as data identifying a user of the device and/or a copy of a program (e.g., an operating system) running on the device. The watermarked version of the buffer content is then made available, such as in response to a screen capture request. The data embedded in the watermarked version of the content is undetectable (or nearly undetectable) to the human eye, but can nonetheless be extracted by other computing devices or data extraction systems.