Search Engines

Search Engines are designed to search for information through the web. We can identify two types of search engines: search engines and directories. With the difference on how result are searched. We can separate them in four main types, crawler-based search engines, directories, hybrid engines and paid search engines

Crawler-Based Search Engines known as spiders or web crawlers, they operate through software in order to automatically identify results to our search. Google is a crawler based search engine.

One of the most important factors you should remember is that a spider cannot ready flash, so even if you create impressive graphics using flash or JavaScript for your customer spiders cannot identify the content and it will skip this part of your page with result your page will rank low and it will not be visible for your human visitors. When you write your contents you should remember that even your human visitor will be attracted from a page full of contents a spider values the text closest to the beginning of your page and the end and further the links you have on your web page. On the other hand a spider can read you meta tags (meta tag description, meta tag keywords etc) your customer does read them.

When a spider will found you page will read it – known as crawling – and will leave a record on your server about its visit. The next stage is to compress the results and store the web pages in a search engine index. All the data are stored in the search engine index in a way that makes quickly to identify if a page is relevant to a particular search and to include in the search results with the most common words and phrases on the indexed page. The search results are according to how relevant your page is to these terms, according to a number of internal and external factors and your page rank.

Spider-Based Search Engines use directories as a source to identify new pages to crawl.

Human-Edited Directories on the other hand the list websites with a different structure. Human-edited directories require manual submission. After you submit your website it will be reviewed from an editor and it will prevent pages from being submitted automatically. An editor will evaluate your website according to the directory’s guidelines and the editor will decide if he/she will include your website in the list. Dmoz is one of the most important human-edited directories.

Hybrid Search Engines, they evaluate sites and scan them to identify for matches. Even Google and Yahoo a directory and crawler search engines, are also hybrid engine. A hybrid search engine like Yahoo usually will present human-edited search and Google will present crawled listings.

Meta Search Engines like MetaCrawler and DogPile will present a combination of results from search engines like Google, Yahoo, Msn and Ask.

Paid Search Engines. There are few paid search engines. There a few advertisement programs that offer pay-per-click and pay-per-performance search results. Google though Google Adwords and Yahoo and MSN they have programs for Paid search results.