I agree with lafmom - there is a certain clique feel about the site - somewhat like moving to a new neighborhood where the people who already live on the street have many shared experiences.
As a long time lurker, I recently decided that I had lurked long enough and was starting to have experiences to share and questions that needed to be answered - so I deliberately started to post.
Just like moving into that neighborhood, you need to make that first move - being taking some cookies across the street or making that first post.
I will say that the way HSBBW could improve is to be more welcoming of the new kids on the block - check to see how long someone has been registered and how many posts they have made before responding. Tempering the words used in the response when someone is new would help to bring that person into the group rather than driving them off...