Yahoo directory is particularly worth submitting a link into in order to get listed on the yahoo search engine. Since yahoo will obviously place higher weight on sites listed in their directory, so it would be expected that a site placed in yahoo directory will improve its ranking on the yahoo search engine.

There are many other directories on the internet. If submitting your website to many directories, it is important to use different text on each directory otherwise the text will be detected as a duplicate and may therefore not be displayed in search results.

If you list your site in many directories then that can be a cheap way to build up links from other sites that point to your site. However, some directories have been removed from Google's cache. Many directories show signs of being updated much less frequently in Google cache's than before.

Directories that are especially targeted are those that sell paid links purely for link spamming. Yahoo directory and similarly reputable directories remain unaffected by this purge. Another measure of the quality of a directory is its pagerank and if its homepage has a pagerank of zero or is unranked, it would be best avoided.

Nevertheless, even if a link ceases to be counted in Google, it may still be worth the time and effort if it means that your website can still be marketed in other search engines like yahoo.

Do not use link exchange directories or directories that require a 3 way link exchange as this can be seen as black hat SEO by Google and could get your site banned.