The option to downvote was initially given to a select group of web users, but Twitter says it will soon be expanding the feature to iOS and Android users as well. Unlike on sites like Reddit, total tallies for upvotes and downvotes aren’t public, but are being used by Twitter behind the scenes to tweak what replies it shows users.

The company said results of the experiment so far found that users downvoted replies they found offensive or irrelevant. “This experiment also revealed that downvoting is the most frequently used way for people to flag content they don’t want to see,” said Twitter. Presumably, this is instead of muting a conversation or flagging it as spam or irrelevant — options that Twitter currently buries within unwieldy dropdown menus.

Twitter’s conclusion so far is that access to downvoting “improves the quality of conversations on Twitter,” suggesting the feature might eventually graduate to become a permanent addition to the site.

Downvotes and dislikes are a simple way for users to give feedback on online content, but they can also be problematic. They can be used in campaigns of targeted harassment, for example, and if they became part of Twitter’s algorithm they could be used to silence dissenting opinion.

In the past, YouTube has found dislikes so problematic that it made the vote-count private as of November last year. Facebook, meanwhile, has experimented with downvotes, but never implemented them, preferring to initially only give users the option to “like” content before expanding the range of reactions using emoji.

NASA’s James Webb Space Telescope was successfully launched on December 25th. This is the revolutionary successor to the Hubble Space Telescope. The spacecraft still has a long way to go in space, but if all goes well, the vehicle could transform our view of the Universe.