Search Engines Optimization has different tools and techniques to work and along with that they have different names for those. Here, we are talking about the web directories and search engines. Literally Web directories are those directories where the SEO expert submits any website according to its category mentioned; whereas the search engines are those who actually use software to crawl for different websites for which people are looking for. It is not necessary that to get your site crawled on the search engines you have to submit it into the web directories; the search engines are capable to find your site through links of your sites which have been used anywhere through their spiders.

The basic differences between these two are that the Search engines are made up with robots, crawlers and spiders; whereas web directories are maintained through the human editors on the web. The examples of Search engines are Google, Yahoo, and Bing etc. And they work to search relevant websites, studying the content of the web pages, and reporting it back to the databases.

To talk more about the web directories then they are like man made indexes of websites i.e. Yellow Pages and they are preserved by the human editors.  They also review the websites available on those directories. Because the web directories do not have any crawlers to find them out they have categories divided according to various topics. Web Directory submission services are available in two types (i) free (ii) paid.

These two are the two services of the Search Engine Optimization and have equal importance of itselves.