There is a URL for a fictional travel site in Uncharted 4 that didn't actually lead to anywhere, so one fan decided to buy it.
Uncharted 4 has an unclaimed URL, so one fan bought it
Some minor, non-story spoilers to follow
In one of the early chapters of Uncharted 4, you get to explore the house where Elena and Drake are living together.
Of the many items you could interact with, one in particular is a travel guide to Bangkok, Thailand's capital, and the place Elena is writing an article about. On the back of this book, you can seen some flavour text and a URL for a fake website.
The website is called http://www.bangkokthetravelguide.com and you can see a screenshot of the book here:
Though you may expect Naughty Dog or Sony to have set up an actual website at the link, the URL wasn't actually owned by anyone, and directed to nowhere. That's until Reddit user Dacvak bought it, without really planning what to do.
As of right now, the site redirects to Dacvak's Reddit post, but they may later have it link back to Naughty Dog's website.