Because no one uses directories these days (people use google/yahoo/msn). 99% visitors of directories are webmasters and directory owners. This is so simple - just ask yourself when was last time you used directory to find site of specific topic?
If you are listed in a category of a directory which ranks for your keywords, you can get some hits. Blog directories give me hits as well. Not that many, but some.
Try submitting your site to some niche directories which match your sites theme. You'll have a better chance to get some traffic. From free general directories, you won't have any hope of getting traffic.
Actually if u submitted to 500 directories with the same description, that is even worse. It's called duplicate content and if you are looking for attention from search engines, they don't like duplicate content. I think a small no. of quality directories is better then 1000s of bulk directories. take care
What have you done to track your submissions? Not all of them will add your site, but do you have any idea of how many rejected or accepted it? You should get a lot of emails back telling you the results. Did you do these submissions yourself? Also, how up to date was your directory list? A lot of free directories turn paid over time.
Excellent points. However, I've come across a lot of directories that don't even have a useful search. Occasionally there's no search at all, and often when there is it doesn't point out all the categories as well. Perhaps this is one reason directories don't get used as much as they could be?
True, and good point. I've seen a few of those, and you got to wonder what the webmaster is thinking.