Make sure to read the help pages of any information retrieval service you use. These pages are designed to show you how to use their specific service most effectively. No two search engines are exactly alike in the combination of advanced features that each supports.
Here are links to the help pages for some of the information retrieval services you have learned about in the preceding modules. Take a minute or two to view a few of these help pages.
Clicking on any of these links will open the Web site in a separate browser window, so you can switch back-and-forth between this lesson and the Web site

1. Google Support
2. Bing Search
3. Ask Search
4. Yahoo search help

To reach the Help section for a directory or search engine not listed here, go to the Main page of the search service and look for a link or button reading Help or Search Help or Search Tips.

Do Directories carry weight? Can they hurt your rankings? Should you even bother? The answer here is yes, yes, and yes.
This section will mainly focus on general directories, but the end of this section does include a few tips on how to find niche directories (or even other general directories) and how to determine if they are worth getting a listing on.

The Yahoo Directory was started in 1994 under the name "Jerry and David's Guide to the World Wide Web" but in 1996 became Yahoo. At the time Yahoo was primarily a directory with search functionality and (interestingly) neither SEO nor Internet Marketing were even categories at the time.
Through the late 1990s Yahoo pushed to become a web portal and in 2000 even signed a deal with Google that would see Google power Yahoo's search functionality. Their focus at the time was to acquire users through acquisitions such as GeoCities (RIP), bringing more people into their portal and keeping them there. Unfortunately Yahoo! did not have the same user loyalty that Apple does and the walled-garden approached failed as users Googled their way out of the Yahoo network of sites (ironically right on Yahoo's own properties). All this said however, they still provide a solid directory (back to their roots). The cost is a non-refundable $299 review fee.

Best of the WebBest Of The Web may be my favorite of the general directories due in no small part to the fact that they allow for a permanent listing. The directory was founded in 1994 as a listing of the best of the web (seems to be the year of directories) and actually gave out a series of awards (take a peek, it is interesting to see what types of things won back then). That lasted until 1998 at which time the site lay dormant until purchased in 2002 at which time it became a general web directory.
BOTW is a human edited directory. They will decline your listing if they do not like the site. A submission is $150 annually or $300 for a permanent listing.

The Directory Mozilla Open Source project. DMOZ was founded in June 1998 as Gnuhoo. It was purchased by Netscape in October of the same year at which time it became The Open Directory Project. By April 2000 it had surpassed the Yahoo Directory in number of URLs in its index and currently sits at about 5.2 million.
For those in the industry long enough to remember, DMOZ suffered a catastrophic failure in October of 2006 at which time they had to display a backup version of their directory. This was not remedied until December and new sites could not be suggested until January. This is he time when it seemingly became increasingly difficult to get a listing in DMOZ as any editors seemed to have found new things to do with their time.
It is still possible to get a listing in DMOZ. For the 10 minutes it takes, it is well worth the time and it is free to submit.
(Tip: try to submit to a category that has an editor.)

Business.com was started in 1999 as a search engine for business and corporations. They came close to bankruptcy during the dot-com bubble bursting but after major layoffs and restructuring they became profitable once more in 2003. Business.com is focused on business-to-business resources (so take that into consideration when thinking about submitting. The cost is $299 per year and all submissions are reviewed manually.
As with Yahoo and BOTW, the fee is non-refundable if your site is not accepted. You are paying for the review, not the link.