Twitter’s blue ticks are a fine example of the Byzantine Generals problem. The blue tick is meant to prove that the Twitter account actually is run by the person it claims to represent. So, for example, an account called “Joe Biden” has a blue tick to prove that it is run by the real U.S. President Joe Biden (or his staff), not an imposter. But blue ticks are allocated through an opaque process run by a centralized team at Twitter, which is not accountable to the Twitter community and is suspected of corruption. Rumors circulate that blue ticks can be bought for $15,000 or $36,000 or some such figure. There’s no evidence this is true, but it doesn’t matter. People believe the rumors, and that is sufficient to destroy trust. The blue tick that was supposed to reliably identify celebrities, influencers, companies and brands is no longer reliable.