I post sticker at place where I have stayed. And on the sticker, there is a unique URL. Through the URL you can see what I saw at that spot.

我在我去过的地方贴下贴纸，在贴纸上有一个唯一的网址，透过该网址你们能够看到我在该地点所看到的。

youdao

If you doubt that, post a Christian cross in one coffee alcove and a Darwin sticker in another.

FORBES: Magazine Article