Secrets of Winning Traffic through Search Engines

How Search Engines work

Internet search engines are special sites on the Web thatare designed to help people find information stored on othersites. There are differences in the ways various searchengines work, but they all perform three basic tasks:
* They search the Internet -- or select pieces of the Internet -- based on important words.* They keep an index of the words they find, and where they find them.* They allow users to look for words or combinations of words found in that index.
Early search engines held an index of a few hundred thousandpages and documents, and received maybe one or two thousandinquiries each day. Today, a top search engine will indexhundreds of millions of pages, and respond to tens ofmillions of queries per day.

Spidering
Before a search engine can tell you where a file or documentis, it must be found. To find information on the hundreds ofmillions of Web pages that exist, a search engine employsspecial software robots, called spiders, to build lists ofthe words found on Web sites.
When a spider is building its lists, the process is calledWeb crawling. In order to build and maintain a useful list of words, asearch engine's spiders have to look at a lot of pages. Howdoes any spider start its travels over the Web? The usualstarting points are lists of heavily used servers and verypopular pages. The spider will begin with a popular site,indexing the words on its pages and following every linkfound within the site. In this way, the spidering systemquickly begins to travel, spreading out across the mostwidely used portions of the Web.

Indexing
Once the spiders have completed the task of findinginformation on Web pages, the search engine must store theinformation in a way that makes it useful. There are two keycomponents involved in making the gathered data accessibleto users:
* The information stored with the data* The method by which the information is indexed
In the simplest case, a search engine could just store theword and the URL where it was found. In reality, this wouldmake for an engine of limited use, since there would be noway of telling whether the word was used in an important ora trivial way on the page, whether the word was used once ormany times or whether the page contained links to otherpages containing the word. In other words, there would be noway of building the ranking list that tries to present themost useful pages at the top of the list of search results.
To make for more useful results, most search engines storemore than just the word and URL. An engine might store thenumber of times that the word appears on a page. The enginemight assign a weight to each entry, with increasing valuesassigned to words as they appear near the top of thedocument, in sub-headings, in links, in the meta tags or inthe title of the page. Each commercial search engine has adifferent formula for assigning weight to the words in itsindex. This is one of the reasons that a search for the sameword on different search engines will produce differentlists, with the pages presented in different orders.
An index has a single purpose: It allows information to befound as quickly as possible. There are quite a few ways foran index to be built, but one of the most effective ways isto build a hash table. In hashing, a formula is applied toattach a numerical value to each word. The formula isdesigned to evenly distribute the entries across apredetermined number of divisions. This numericaldistribution is different from the distribution of wordsacross the alphabet, and that is the key to a hash table'seffectiveness.

The search engine software or program is the final part.When a person requests a search on a keyword or phrase, thesearch engine software searches the index for relevantinformation. The software then provides a report back to thesearcher with the most relevant web pages listed first.Is Your website search engine friendly? If you have anydoubts, it may be time to take a look and make your own “bigbreak”.