[Endama]

Twitter needs some kind of negative feedback mechanism to allow for the discovery algorithm to correct for the sentiment of users. A downvote, dislike, un-heart, something along those lines, would be a good signal to allow users to signify what kind of content they deem objectionable.

[tomatotomato37]

Downvote-type systems aren't that effective since they usually end up becoming a "I disagree" button and multiply the effect of whatever mob is most active at the moment. It's one of the reasons HN locks them behind a karma wall.

[Yetanfou]

Even that is not an effective way to avoid the negative effects of the downvote button, especially not here on HN where it actually is meant to be used as a "disagree" button:

https://news.ycombinator.com/item?id=117171

The "karma wall" only keeps the downvote option out of the hands of those who follow short-lived "mobs", it does nothing to stave off the balkanisation of the platform.