Device-to-device audio communication (think QR codes, but made out of sound) seems very underrated. Much better UX than QR codes or NFC because you don't have to worry about putting your phone in the exactly right place or pointing it in the right direction.

Anyone here with more detailed takes on this?

Beacon technology also seems underrated to me. 

You can give a free mint to anyone who enters a store and have a specific app downloaded.

Could be great for rewards programs.

.tokenizing imagination @ merv.wtf .funding the new internet @telah .founder 
@kaizendao .host /esoteric

Played with this concept in 2015 in a few shopping malls and a large stadium using Ruckus access points...worked well but was a bit too early...