One excellent way to build that "billboard" for your site is through the search engines. "Search engine submission" refers to the act of getting your web site listed with search engines. Another term for this is search engine registration. Note that getting listed does not mean that you will necessarily rank well for particular terms, however. It simply means that the search engine knows your pages exist.
Search engine optimization (SEO) refers to the act of altering your site so that it may rank well for particular terms. Terms such as search engine placement, search engine positioning and search engine ranking refer to a site actually doing well for particular terms or for a range of terms at search engines. This is the ultimate goal for many people -- to get that "top ten" ranking for a particular keyword or search terms.