This way, forum users never have to see the WP backend, and they will have the ability to change their forum nickname.

How could this be achieved?
I'd happily add this myself if I had the PHP know how :P

I didn't go that route since loading the entire WordPress API's a bit heavy for something as simple as this, and slows down my site's page load time a lot. So I made a function similar to what ScottDavis did and went with that.

Not sure if you forgot to mention this, but with at least my setup get_author_name() is not an available function. I created one and put it in header.php:

function get_author_name( $id ) {
$user = bb_get_user( $id );
if ( empty($user->display_name) )
return $user->user_login;
return $user->display_name;
}

[topic.php]
replaced get_topic_author()
with get_author_name( $topic->topic_poster )
replaced get_topic_last_poster()
with get_author_name( $topic->topic_last_poster )

[frontpage.php and forum.php]
replaced topic_last_poster()
with echo get_author_name( $topic->topic_last_poster )

[profile.php]
replaced echo get_user_name( $user->ID )
with echo $user->display_name

and so on..

for post.php - if you want the display_name wrapped in a link you can use this slightly modified version of post_author_link()

function my_post_author_link( $post_id = 0 ) {
if ( $link = get_user_link( get_post_author_id( $post_id ) ) ) {
echo '<a href="' . attribute_escape( $link ) . '">' . get_author_name( get_post_author_id( $post_id ) ) . '</a>';
} else {
echo get_author_name( get_post_author_id( $post_id ) );
}
}

i put the function in my header.php file for now.. until i find a better place for it. then, i replaced the call to post_author_link() in my-templates/post.php with my_post_author_link()

there's probably a better/shorter way to do this, but to be honest, i think i prefer dealing with display_names as a template issue. I mean, shouldn't we be modifying the display_name on the way out of the database instead of on the way in? This way, if i ever decide to deactivate this plugin (as i just did), i am not left with a mashup of WP display_names and bbPress topic_poster_names in my db..

disabling the "Use Display Name" plugin fixes the issue.

But at the moment, I cannot decide that the bug is in the plugin - it may be a bbPress bug as well. Someone has to look at it.

There is a thread in the forum for this problem, which shows, that this bug causes a lot of confusion.

*No permission to create forums
*No permission to delete posts
*No permission to add more than one tag
*No permission to edit posts

Basically, seems like the usual keymaster rights aren't working.

Thanks!

function bb_use_display_name_profile_link($r, $id) {
	$user_obj = new BB_User( $id ); //Mod
	if ( $user_obj->has_cap('moderate') )  { //Mod
		if (  bb_get_option( 'mod_rewrite' ) === 'slugs') {
			$user = bb_get_user( bb_get_user_id( $id ) );
			$r=str_replace("/profile/".$user->user_login,"/profile/".$id,$r);
		}
	}  // Mod
	return  $r;
}
add_filter( 'get_user_profile_link', 'bb_use_display_name_profile_link',1, 2)

I can force it to trick the link to use the display name but on the destination, the profile.php does not know how to interpret the display name.

Okee I'll work on this for a bit, I think the solution is to just use the user id # instead of the name when it's a mod.

TADA!
add this to display-name.php to force mods's profile links to use their id #'s instead of their login names when "slugs" are enabled - everyone else still gets pretty slugs

function bb_use_display_name_profile_link($r, $id) {
	$user_obj = new BB_User( $id ); //Mod
	if ( $user_obj->has_cap('moderate') )  { //Mod
		if (  bb_get_option( 'mod_rewrite' ) === 'slugs') {
			$r = bb_get_option('uri') . "profile/" . $id;  // . ( 1 < $page ? "/page/$page" : '' );   not sure how to handle pages since they aren't passed
		}
	}  // Mod
	return  $r;
}
add_filter( 'get_user_profile_link', 'bb_use_display_name_profile_link',1, 2)

Doesn't handle pages on profile links though. Not sure how to deal with that. I could take the orignal link build and just do a search and replace for their login name to the id # .... hmm...

thanks for the plugin....

add_filter( 'get_topic_last_poster', 'bb_use_display_name', 1, 2 );

(you have the one without the echo/get_)