Fly-by user

From eg

A fly-by user is one that leaves a single comment on a blog or wiki without login and with no particular promise or implied intent to return.

Remaining open to such input is a wiki best practice and has been widely credited with creating Wikipedia's success. Some wikis do require a login but it is quite easy to create a disposable one under a troll name.

A troll-friendly wiki is optimized to receive input from such users and their new troll point of view, while shutting out spam.

Some less friendly do at least make it possible for users to participate in tagging, e.g. by votes. See repute for good reasons not to rank users in this way.