Maybe useful for someone else: this is a patch of wp-includes/category-template.php to return an array of the tags instead of printing it when using the “format=array” option in wp_tag_cloud().
This seems to have been fixed in version 2.5, let’s see that soon! In the meantime…
we should check the track more often:
http://trac.wordpress.org/ticket/5155
there was a ticket for the same ticket there
Comment by jerome — March 25, 2008 @ 9:55 pm