Here’s a simple way to help users to contribute to your forum:
Make the area to Log in or Sign up as obvious as possible
It is very difficult to get users to contribute unless they’re signed in. While it could make sense to solicit replies, then have users log in after they’ve written something we prefer the more conventional approach because when a user is logged in, it allows him or her to make other contributions to the forum (repping posts, filling out their profile info, posting pictures, etc.).
It is still surprising to study forum software that obscures the user registration area. Click on any of the screen caps below and time yourself to see how long it takes to find the Log in or Sign up buttons. See if you can figure out which screen cap is from a Ninja Post forum and which two are from legacy platforms.