Just because a person doesn't post on the forum doesn't mean he doesn't read the forum. I joined the site in April 2011 and read the forum for a month before I decided to join it and post. There are many times up to this very day that I read the forum without posting anything; whereas, there are others who seem to be compelled to post even it is just a few words almost every time they access the forum.
That's all true enough Stowe. There are plenty of ways to deceive people in the forum in regards to all of the many ways you mentioned above. Somebody can "lurk" in the forum for years as a non-posting member or as a "guest" who can read everything going on but has no posting privileges. But just because somebody can, doesn't mean that they have. lol