Promotion comes in many forms.
The most obvious form of promotional advertising for a web site is listing with search engines and directories. It just makes sense to concentrate on the big boys where the effort will do the most good. Check the very, very small print - You'll find that those guarantees only apply to one or two key words in one or two search engines. Every site is different, every key word is different, every search engine is different even at different times of the week or year. Some are hand edited, some are months behind.