Active Print and Digital Displays
Codes can be just as effective alongside content on digital displays as on printed matter. LCD and plasma technologies are both OK for displaying codes, but cathode ray displays produce scan lines that interfere with code reading.
For example, the following code in this web page enables someone running Glass on their camera phone to take away a mobile link.
Codes can also be effective on public displays such as plasma screens or PrintSigns.
Then there are the displays on phones themselves. Glass has a feature to display a code that was captured earlier, so that someone else can capture it from your phone. Another example is where codes on a phone display are used as a voucher.