A lot of forums have minimal participation, one of the better ones has been Nikonians. Unfortunately in recent times, it seems like revenue is more important than helping others. In the past you could register ask questions and share knowledge for free. Then a culture shift took place, and if you wanted to post or use more advanced features an annual fee was required. Now the site has backed off from the payment a little, by giving you credit for posting. However, if you fail to post regularly and choose not to pay, you are prevented from reading posts.
It just so happens that certain founding members collect a good deal of revenue from advertisements and new memberships. But the whole concept that made them successful was a free exchange of ideas and support for fellow photographers. Why should experienced photographers have to pay a fee to volunteer their time to a forum answering questions. I think the premise of charging to participate stifles ideas and is counterproductive.
I hope that another forum with photographers devoted to Nikon equipment will evolve that keeps the door open to the free exchange of ideas and support. It would be nice to see American photographers put together a new site that host sections for both Canon and Nikon. A site that is not competitive, and just leads to a healthy exchange of ideas, support and opinions would be welcomed.
One forum that is worth checking out is: http://www.dpreview.com/forums/ They have a good deal of active posts daily and the site is free.