In a prior life I set up dozens of forums. Mary is exactly right. One of the causes is fear of being picked on by the regulars in many forums due to lack of expertise with a computer.
"OH NO NOT THAT QUESTION AGAIN" responses when it is the persons first post. That will make many a lurker forever.
A well run forum with lots of information will answer lots of questions for them without signing in too.
There is a function on the board that will require login for us to see the threads. If you do that, they will log in but still won't post. Age old mystery
