I do not like junk mail. Which is why I have a No Junk Mail sticker on my letterbox. It's meant to stop catalogues and flyers, although is frequently ignored by businesses big and small. Last year I got six from one pizza shop who each time assured me it wouldn't happen again. They always blame the distributors. It's difficult to find research on how many Australian households have these stickers, so I conducted my own with a sample of 500 properties. (Happy to admit this was not random, but based on the first 500 mailboxes I came across in the northern suburbs of Melbourne.) 30.4% had No Junk Mail signs. I wondered, what would be the impact if the junk mail system was opt-in, instead of opt-out? As behavioural economist Dan Ariely tells us, the default option in a system has a significant impact on how we make decisions. We see this most dramatically in organ donation around the world, where countries similar in culture, religion etc. have very different outcomes. The critical factor is opt-in versus opt-out. [caption id="attachment_1201" align="aligncenter" width="474"] The difference between opt-in and opt-out of organ donation.[/caption] A month later I measured how many had been removed and how many remained. 61.3% of the No Junk Mail stickers were still on the letterboxes.Applying this thinking, I conducted an experiment by printing 150 No Junk Mail stickers and placing them on letterboxes around the neighbourhood. Imagine our junk mail system was opt-in instead of opt-out, where people would put a Junk Mail Please sticker on their letterbox if they wanted to receive catalogues. We'd shift from 30.4% of households not receiving junk mail to 73.6%. [caption id="attachment_1202" align="aligncenter" width="470"] The difference between No Junk Mail and Junk Mail Please systems.[/caption] The industry would more than halve over night. And so too would the landfill.And this doesn't account for how much harder it would be to source a Junk Mail Please sticker than taking off one of my homemade ones. Nor does it account for the social norming which would shift perceptions once it had a majority. Of course, the marketer in me knows the channel is an effective one. Retailers invest in catalogues because they work. I have a client whose most successful marketing activity to date was a fridge magnet drop. Doesn't mean I wouldn't mind seeing the end of junk mail though!...