You need to set the $user_id in order to get results, for example if you want results for the current logged-in user the your widget code should look like this:
//first check if a user has loogged-in
if (is_user_logged_in()){
// then get the current user id using get_currentuserinfo();
global $current_user;
get_currentuserinfo();
//then use the plugins class: and pass the current user ID
$baur_plugin = new baur_Plugin();
$user_rank = $baur_plugin->ba_get_user_points($current_user->ID,true);
echo "title: ". $user_rank['title'] .
"<br />Points: " . $user_rank['points'];
}
