Search Engine Optimization
Search engines use robots called spiders to
index your website. Submit website to a particular search engine and the spider will index your submission. Here is how it works: A spider which is also called a crawler, visits your website, reads your page and then
follows links to other pages within your site. This is what is meant when someone says your site has been spidered or crawled. The spider will also return to your site on a timed and regular basis say once every couple months to look for any new changes. Once the spider has all your information, it goes back home to the search engine where it will begin to index what it has found. Most of the time, it can take a while for new pages to be added to the index. Thus, your website may have been spidered but
not yet indexed!
Until your site has been indexed, you are not yet available for search because your site do not exist yet as far as consumers are concerned. Now, some promotional gurus say that you do not have to actually submit your website to these deep search engines because in theory, these robots are spidering new websites everyday and supposedly they will find and index your site eventually.
But the reality is that unless you have links from other sites leading to yours, or you have submited your site with one of these search engines, your website will not be indexed, hence you will never exist! So, there is confusion whether search engine submission is needed or not. My suggestion, it is need to submit your site to search engine in order to index your site faster.