How to add this feature https://en.blog.wordpress.com/2010/08/03/like-a-post/

Try searching for plugins: https://www.ads-software.com/extend/plugins/search.php?q=like&sort=

It looks like all the working ones are Facebook like.

Unless I am unable to find it or I am missing something obvious, it seems like that this feature: https://en.blog.wordpress.com/2010/08/03/like-a-post/ is not opensourced or available for download. Its sad if that is the case.