While Jim is absolutely correct, if you were to spend some quality time in the SEO forums you would find answers all over the map.
Some argue that we are obsolete, of no value, and our parents dress us in funny clothes. They may or may not be correct.
Some argue that a listing in the directory is nice, it is not critical to a site's success. They may or may not be correct.
Some argue that a listing in the directory is essential, it is critical to a site's success. They may or may not be correct.
We're too busy building a directory to worry too much about what they say in SEO forums. We say:
Build a site for websurfers with lots of unique content, let us know about it, and we will consdier listing it. We also note that people who build websites for websurfers, and pack it with lots of unique content often find they are listed long before they thing of suggesting the site.