YouTube announced today that the Dislike button will not show the number of dislikes anymore.
According to a public statement on the YouTube blog, the
dislike count will be private across YouTube, but the dislike button will remainYouTube
The reason for changing this actually makes sense, as "dislikes" are often used by haters and trolls and can seriously impact the mental health of the video creator. The YouTube team did an experiment focusing on exactly this topic and found that users were less likely to push the dislike button when the number was not shown.
From a technical point of view, developers may need to re-program some of their code. Because this change also has an effect on the YouTube API. The number of dislikes of a video could be read by the dislike_count field.
Only developers filling out the exemption application form will (maybe) granted to continued access to the dislike_count statistics.