If, on http://drupal.org/project/themes/ , I search for "lc3_clean", I get "0 Themes match your search", while there is a theme with exactly this name. If I search for "lc3 clean" instead, I get 146 results, but the theme "lc3_clean" appears only on the 3rd page. But if I search with Google '"lc3_clean" site:drupal.org', I get the right theme immediately. Generally speaking, for both modules and themes, the search functionality is quite bad. It seems that the title is not seriously taken into account as search criterion.