tangor - 5:51 am on May 30, 2010 (gmt 0)
Maybe I'm missing something in the OP's query. Directories are lists. Most are opt in, ie. a beg to be included and are nothing more than "yellow pages". Or the "directory creators" are trolls inserting entries in a "yellow pages" to arm twist others. I use that term to make sure folks understand that search engines are white pages (inclusive of all) and directories are yellow pages, that other book, mostly pay to be included, which is a subset of the white pages. I am not impressed with "directories" and generally do not waste time on them. Heck, most of the time I don't even google... I bing... and I do that because bing is more about service and results.
Long and short, I see "directories" as link farms. Pretty sure I'm not in the minority in that regard... FWIW, YMMV, IMHO.