Conclusion - So we could see from the article above mainly emphasizes the fact that Web Directories must not only be seen from the SEO point of view http://ping.fm/GO2UA - i.e. for getting Link Juice and Page Rank or Backlinks but also must be seen as a instrument to get targetted traffic.
This could come only when the directory has better SERPS or ranks high for various keywords which are infact categories of the directory so that those category pages get visits directly from the Search Engine Result Pages (SERP)
which finally goes to the links listed on the particular category page.
This could be achived by various methods like adding content to the web directory, getting backlinks directly pointing to the category pages from relevant sites.
http://ping.fm/W9NxJ