Here’s the deal. They’re alike but different in some ways, and that’s where the trouble sets in. What is the basic difference between web directories and search engines?
First, let’s define the following jargons. Search engines normally use a program commonly referred to as spiders, produced through a special algorithm of webmasters. These spiders crawl the many websites, looking for any updates or new contents. Should such programs find something useful or relevant, or any fresh information, these crawled pages will then be “indexed,” become part of the search engine’s database, so they will show as search results.
Even if you don’t submit your site to these search engines, you’ll likely have your site indexed anyway. However, it will be more effective if you settle for an effective link building as it’s through links that spiders find their way to your webpage.
Web directories, on the other hand, make use of categories–like the ones you see in the yellow pages. They are commonly managed by humans, which act as reviewers or editors. So your inclusion will depend on the criteria set by these directories.
There are two kinds of web directories, paid and free. Either way, you won’t be found if you don’t submit your site to them. This is because they don’t have “crawlers” or spiders unlike those search engines. Your appearance in search results will depend on some factors such as your category, your page rank, title, or popularity, among others.
There are, however, instances when a particular site can function both as a search engine and a web directory. Let’s take, for example, the famous Google. Primarily, it is a search engine, with its own Googlebot, the spider. However, it also has its own web directory, as in Google Directory. This directory is considered to be a “spin-off” of DMOZ, an open project directory. Another will be its famous counterpart, which is Yahoo!. Initially, this site was a web directory until it grew immensely and switched to search engine.
How are these information necessary? Very, especially on the webmasters. You simply base your judgment on their definition. Your ultimate goal is to be visited by these spiders so you will continuously be indexed in search engines. Thus, you need to develop a very efficient linking strategy for that. On the other hand, you also have to take advantage of web directories. Most of them are free, so you don’t have to worry any cost. They are also ideal for link backs so you’ll have higher chances of being discovered by search engines’ spiders.