How Did They Do This?

[ssura]

I was on FaceBook and saw a bunch of people commented and shared this Harry Potter related post that said:

When people typed it in, the preview for the link "h-o-g-w-a-r-t-s.com" showed a different house for Harry Potter. The website redirects you to another website with a Harry Potter quiz.

Couldn't help but think about all the traffic it got because of this...

 

[Ryuzaki]

They probably have a list of Meta Titles, Images, and Descriptions that they randomize and roll through on every page request. I've done something similar with PHP and Python separately. I'm sure it can be done with Ruby, Javascript, etc. Anything that renders before the page load is finished, unlike jQuery.

 

[Jooky]

I don't see this being different for each user since FB caches the preview info. They could change it every few minutes like Ryuzaki mentioned but then would have to force an FB cache rescrape via the API:

https://stackoverflow.com/questions...-api-to-force-facebook-to-scrape-a-page-again