Hello Karen
Did you find something suitable?
There are several bulletin board platforms available (SMF, VBulletin, phpBB, MyBB are some common ones). How secure you make your board is up to you. You can keep all content private (not for public view) and select who can access the board and content. You can also have a secure connection [htpss] for a small annual cost. With VBulletin, you can incorporate blogs (for journaling) with the boards. You can also keep the blog private (for members viewing only),
I hope that helps. My apologies if that is not what you meant!