One idea that might help, and this has to be kept in mind by posters somehow, is to give some type of appropiate comment or follow up (if it's that type of post) to the post at hand. Many times a person takes the time to post and it is ignored or passed over like it never happened--so the poster may assume "why did I take the time--no one gives a heck". This can discourage posting, especially by those who don't post often. OR, the next post after someone posts is about something that doesn't even relate to the previous post and may just relate to something regular posters care to talk about--again ignoring the previous post.

The visitor numbers and number of new forum members joining regularly seem like a tremendous resource to tap into somehow, both for growing HL and lighthouses in general. Maybe someone(s) could take the time to ask new members personally as part of the welcoming process or a new members survey or whatever, what they would be interested in discussing. Followup of new members might also be helpful to get their ideas and feelings after they've been a forum member for awhile. These ideas may reveal or give a clue to new forums to be added or old forums to be dropped.