You should know about DIRECTORIES

1. Not all directories are created equal.
2. A link to your Web site in a reputable directory can have a positive effect on ranking in search engines.
3. One good directory to be in is Best of the Web.

The best way to naturally build links is with quality, relevant content. But how do we get the initial visibility for our quality content?
Listing in a high quality directory is a good place to start. Directory listings may not offer much traffic these days, but they can help get your site indexed by search engines and build some trust.
It's important to remember that not all directories are equal. Some are great, some are are junk, and some are in between. Google is known to trust some directories more than others. Usually the ones with human editors, that charge a fee and don't accept just any submission.

Are these directory links worth it?

Trust is a big factor with Google and other search engines these days. Directories that impose strict editorial control and don't accept just anyone boost the trust factor in Google's eyes. It makes that directory and the link to your site, a trusted link ... this is a big deal.
If you're a spammer, you're unlikely to spend hundreds of dollars to try to list your site in quality directories, only to be rejected. Therefore, if you are considered to be a serious, quality Webmaster, and able to get listings in quality directories, Google recognizes that.