Yahoo makes no sense to me. I have one website in the directory for 10 years, they added it not me. Yet, only the index page gets into the search results. They don't even spider the website, its an authority website with no ads, spam, or any malicious. I've emailed Yahoo about it numerous times over the years to inquire about it but never get a response. I have even posted a question about it on their webmaster blog, but that was ignored as well. So, the website is good enough to be in the directory for years yet not good enough to be spidered and in the search results? Bizarre.
I think most people have never heard of the Yahoo directory expect maybe for webmasters. Most people Google and now Twitter Search.