I was thinking about bank clocks that show the temperature and time (perhaps a little more common when I was young). I thought about how nice it would be to put up my own electronic sign that provided information I would find handy and if anyone else would enjoy it. Weather, local events, etc.

Most of the signs around me aren't there to be of use, it's to advertise or at best push some information from someone who had a particular incentive (or even incentive to not show it in this case). I wonder if individuals might make better choices.

Granted, the classic mental illness car with signs all over it might indicate the downsides of letting just anyone do it.