I've been wondering how one could efficiently and reliably pack arbitrary data into YouTube videos, a hacky way to get free and obfuscated data storage. Streaming QR codes has been the most promising way I can think of, particularly since they offer resilience against YouTube's video re-encoding process and are standardized for far larger codes, which could be easily fit in a video for later parsing out by a tool. You could probably embed even greater data densities with a color QR solution too.