i am very thankful for this code
<?php $order = 'user_nicename';
$user_ids = $wpdb->get_col("SELECT ID FROM $wpdb->users ORDER BY $order"); // query users
foreach($user_ids as $user_id) : // start authors' profile "loop"
$user = get_userdata($user_id);
that i got from here:
and that produces an output for each author of a blog.
Does anybody know, how to modify it to do something for each category?