Someone who finds a particular thread offensive and rather than politely PM the member who posted it, with a polite message to please remove or edit the offensive manner ....contacts a Moderator and starts crying like a baby.

Someone who collects online forum posts over an extended period to read them quickly all at once.

A post whore is someone who types thousands of messages on an online forum, mostly with little or no meaning. These people post at least 50 times a day, mostly consisting of one word posts or emoticons.

An Admin or Moderator who is very small in their non PC who abuses the trust and power given to them in order to direct discussion, traffic and post to suit their personal agenda.
Actions include locking, and/or editing post that contain information that is contrary to their own opinion.

I.E. Craydaddy on the salmoncrazy forums

A person obsessed with being the top poster on a forum.

One who leaves forums to garner attention and pity from forum members.

One who creates a thread on a forum and continually posts comments after every reply. Most of said comments are useless, and are only an attempt to keep the thread going.