I use this function to display comma separated terms from a custom taxonomy:
// Get Comma Seperated List of Custom Taxonomy //
function the_custom_taxonomies($taxonomy) {
global $post;
$terms = get_the_terms($post->ID, $taxonomy);
$counter = 0;
if (!empty($terms)) {
foreach ($terms as $term) {
echo $term->name;
if (++$counter < count($terms))
echo ", ";
}
}
}