Peer-to-Peer Accountability Enforcement/purpose

It is easy for malicious, misinformed, and uncomprehending users to greatly reduce the efficacy of civil discussion. I'll refer to these collectively as "malusers" for now, although the majority are probably not deliberately or knowingly malicious.

Malusers generally fall into one or more of the following groups:
 * trolls
 * astroturfers
 * propaganda victims

The involvement of individual malusers in a discussion frequently has the following adverse effects:
 * throwing the conversation off-topic
 * injecting false but believable information
 * making false claims that require extensive research to refute
 * failing to understand the arguments of others

It should be noted that many malusers are known for being unreasonable only on specific topics, and entirely reasonable on others.

While blocking and banning (currently supported by most social media venues) are generally effective ways of dealing with malusers when they are identified, those techniques have a number of shortcomings:
 * it is too easy to block someone who is making valid arguments that you happen to disagree with
 * blocking is fundamentally hierarchical:
 * one person owns a thread or post, and has the sole authority to block individuals from commenting on it
 * a group of admins have the sole authority to ban individuals from posting in that group; there is also typically a single owner or founder who can demote or block admins
 * blocking is a very crude level of control:
 * typically, the only way to block someone from posting on a given thread is a person-to-person block -- preventing the two of you from seeing anything said by the other
 * blocking someone from posting in a group prevents them from participating in any discussions in that group, including topics on which they are more reasonable
 * once blocked, there is no reliable process by which a reformed maluser can regain posting permission

A better solution is needed.