So might we all, in some not-so-distant future, have our own “robots.txt” – a signal that we can instrument at will, one which is constantly on, a beacon which others can pick up and understand? Such an idea seem to me not at all far fetched. We already all carry the computing power and bandwidth on our person to effect such a signal. All we need is a reason for it to come online. Glass, or something like it, may well become that reason.