the postprocessing effects if very simple, you just apply a glyph (even random) instead of a pixel. So if might be used in lots of places... like you mention - for camera input.
This was done 13 years ago for Desktop, C++... but now WebGL would be definitely a better choice.
webscript that picks a live streamed security camera that occcasionally has a people walk by it (ie street cam), based on the users location/timezone
and then asciivideo that in the background of the stream
might try this if i have the time :D. very cool stuff btw