You need search engines to bring your website to the attention of prospective customers. So it is better to know how the search engines really work and how they present information to the customer that is performing a search.
There are basically two types of search engines. The first is by robots that are called web crawlers or spiders.
Most Search Engines use spiders to index websites. When you complete the required submission page for each search engine their specific spider will index your entire site. The "spider" or "web crawler" is the automated program run by the search engines that visits the web site, reads the content, meta tags and follows the links that the site connects to. The spider returns all that information back to the central index of the search engine. Some spiders will only view a few levels of pages on each site so there is no sense in creating a 500 page web site.
Spiders will periodically return to the site to check for any new information or changes to existing information. The search engines determine this period themselves however with one of the major search engines like Google, you can set specific meta tags to tell the spider to come back after a specified period of time.
The spider is like a table of contents in a book, the actual content, links and references for all the websites it finds during a search are indexed. Some search engines like Google might index billions of pages per day.
When you ask a search engine to locate information, it is actually searching through the index which it has created and not actually searching the Web. Different search engines produce different rankings because not every search engine uses the same algorithm to search through the indices.
One of the things that a search engine algorithm scans for is the frequency and location of keywords on a web page, but it can also detect artificial keyword stuffing or spamdexing.
Then the algorithms analyze the way that pages link to other pages in the Web. By checking how pages link to each other, an engine can both determine what a page is about, if the keywords of the linked pages are similar to the keywords on the original page.
If you produce quality content then you don't really have to worry about much since the search engines will quickly decide if your site is relevant and valuable
