So I was just trying to search for the_catillac_cats and I was greeted with a big, fat "No posts matched your search". I snooped around some more find out this abomination of a tag, heathcliff_&_the_catillac_cats, is what the site uses.

The Catillac Cats Wikipedia article reveals there was very little crossover between the two series, and cleo_catillac, who, lets be honest, is the reason for 95% of the heathcliff_&_the_catillac_cats posts, never even appears in a Heathcliff episode. Conversely, Heathcliff himself NEVER appears in a Catillac Cats episode.

This amount of crossover is basically negligible, and I think it would make more sense to separate these series into two different tags: the_catillac_cats and heathcliff_(series).