BuddyPress.org

i ‘ve success change buddypress activity stream default option with multiple option, you just put this in functions.php in your theme.

function blog_posts_by_default( $query_string ) {
global $bp;
if ( !$query_string )
$query_string = ”;
if ( ($bp->current_component == BP_ACTIVITY_SLUG || !$bp->current_component) && !strpos($query_string, ‘type=’)){
if ( strpos( $query_string, ‘action’ ) == 0 )
$query_string .= ‘type=activity_update,new_blog_post,new_blog_comment,new_forum_post&action=activity_update,new_blog_post,new_blog_comment,new_forum_post’;
}
return $query_string;
}
add_filter( ‘bp_dtheme_ajax_querystring’, ‘blog_posts_by_default’ );

you can see the result here: http://blog.uin-malang.ac.id
i hope it run well in your site..