Advice on getting my community's forums popular again

[CombineGuru]

I run a community - SDB - and we have forums at [url]http://www.diamondbuild.info/vbulletin/[/url]

We used to get around 150 - 250 posts made per day, and lots of active forum members, but for some reason now we only get 10 - 20 posts per day and only about 3 active forum users.

I run a 32 slot RP server and two 14 slot build servers, all 3 servers are full for most of the day, with a few players in at night. Lots of players, so that's not a problem.
Unfortunately I can't get any of them - even my admins - to post on the forums, hardly any of them even want to register?

Is there any good way to get my forums popular again?

[Shepsie]

Possibly an exclusive in game item if they register on the forums.

[|FlapJack|]

Offer a hat or something in return for registering. Use OpenID to tie their ID to their forum user account. Fizzadar had an idea back when he ran winsauce - give "coins" for forum posts. These can be used to get ingame shit. You could also gain coins ingame.

Was never finished, due to winsauce shutting down.