had an idea with NFC chips while listening to the podcast. but it would require to visit the place 2 times. Frist to take the photos and write a post about the place and then to put the sticker with the post link programed to it there.
With something like TAP HERE TO KNOW MORE or what ever. And it is better than QR code because you can program specific different link for every place on the same sticker. (the price of it is probably around 10eur for 50 pcs)
I think inleo mentioned something about sharing a link of a post has a referral code in the link, so maybe it could also be used to see if people are making accounts from it ( @khaleelkazi could confirm if they added that).
peakd has a decent viewcounter so that could also be interesting to see are people "clicking" it.