Yahoo! Directory Registration

SEO Question: Is a Yahoo! Directory registration worth it? How do I know what directories are worthwhile? What directories should I submit to? Do you have any good site submission tips? SEO Answer: If you have a business, and are serious about SEO, I generally would recommend submitting your site to the the blogs category rather high in their overall category structure. Want another example of a directory category getting a bit of overexposure? When Yahoo! created their own search engine, their SEO resources category. Hundreds of companies listed in the web directories and SEO is a good primer for considering the quality of various directories, and how search engines may evaluate them. A couple things I would add to that post:

Aged sites and/or sites with clean link profiles which are well trusted in Google are given a bit more leniency on what links may count and how many bad links they can get away with. If you have an aged trusted site you may want to dig a bit deeper for links, but for newer or untrusted sites you are best off just getting links from some of the higher quality directories.
If you are applying to become an editor at DMOZ, or other volunteer ran directories, make sure you start with a small category and sell topical passion more than you sell your commercial interests in the topic.
If you submit to a directory which allows multiple deep links with your listing, like Business.com, make sure you consider what pages will earn the most. For example, I have a 600+ page site where about 20% of the earnings come from one page. Getting your top earning pages a few more links can significantly increase their earning potential, but also note that if your deep idea is an uncompetitive niche there might be other links that you can get that will not leave such an obvious roadmap for competitors.
If your brand or core keywords could commonly be misspelled, like Client Side SEM vs Clientside SEM, you may want to submit your site to a couple average to lower quality directories with misspelled anchor text.