Facebook says it is not testing a “dislike” button, but rather a “downvote” option, which would let users flag abusive or inappropriate comments.
News of the beta test broke on Twitter when screenshots of the feature began to circulate. Facebook later confirmed the test to media outlets.
Tapping the downvote button hides the comment for the user who taps it, then asks them to say whether the comment was “offensive,” “misleading,” or “off topic.” Downvote view counts not being visible to users. “We are not testing a dislike button,” a Facebook spokesperson writes. “We are exploring a feature for people to give us feedback about comments on public page posts. This is running for a small set of people in the US only.”
Many speculate that if it is rolled out as a permanent feature, it will start small before being offered globally.
The Verge continued:
It seems likely that the downvote button, if it does ever launch, will start off restricted to public posts as a way to help users self-moderate sprawling threaded comment sections under news articles, as an example.