As an owner of another forum (in a another language and about a different subject), I want to suggest to install the following plugins which I have installed in my forum:
• Add the "Unread posts" link to the forum main menu. It should display the list of the topics which have posts the user has not read yet.
• Email notice about quoting. The author of the quoted post receives an email with the link to the post which contains the quote.
• User mentioning mechanism (BB code [user]<user name>[/user]). The user, whose name was mentioned in that BB code, receives an email with the link to the post where he/she was mentioned.
• The micro-profile (user info under the avatar) should contain this info:
registration date
number of posts
number of likes
sex
location
the last visit date/time
• Similar topic service. When user starts to create a new topic and types the title, existing topics with the entered words should be displayed. Maybe, such a topic already exist, so the user can write there instead of creating a duplicate. Alse, when an existing topic is opened, the list of a few (5-10) similar topics (if exist) should be displayed at the bottom.
• BB codes validation before save (with error message if needed). For example, the closing bb code is missed, or bb codes are nested incorrectly.
Good luck!