Understanding PageRank doesn’t get you very far if you are not indexed in the first place.
If your page (or site) has inbound links from sites in a search index, then Google (or any other broad search engine) will most likely find you pretty quickly. However, it’s peculiar but true: different search engines index different portions of the Web. Also, at any given time, it is impossible for any search engine index to include the entire Web!
To avoid being left out, it makes sense to manually add your URLs to search engines. (In early times there might be more of a delay before your sites were found, and it really made sense to make sure you were listed!)
Be careful to create pages that are friendly to webbots—which constitute the advance scouts for search engines—as I explain later in this article in "Working with the Bot.”
Getting listed is, of course, only the beginning of the battle. One of the key goals of core SEO is to get both highly ranked and listed in reference to some specific search terms. Achieving this goal requires taking affirmative control of the information that the search index may use to make ranking decisions—and that it will use to understand the quality of your pages.