Directories used to be important in the mid-1990s, as they tended to provide better search results than dumb link crawlers like Altavista. Yahoo started off as a human-edited hierarchical directory of links and adopted the crawler approach later.
However, since Google has come along with a better search algorithm, directories are in decline. dmoz is the only major one left, and this hasn’t escaped the notice of SEO folk, who chase the prestigious linkback and fill the submission queue with a lot of crud.
Feel free to suggest a URL for inclusion.:-)