There are many techniques and methods able to be employed by sites or administrators wishing to utilize SEO services. The ones used and in what combination differ from SEO provider to SEO provider, and all methods potentially have positive and negative capabilities. An essential key to search engine optimization involves the keywords that will be used to drive traffic to the site. Selection of the right keywords will allow users directed from a search engine to find the specific topic or keyword for which they were searching. Selecting less popular keywords may also help boost a site's listing on a search engine. Link building (whether paid or free) present users with useful links outside of a traditional search engine. Positioning links on related websites will generate traffic from users desiring information or services offered by the site. Successful link building can often be done for very low cost and many times without the aid of a search engine optimization company.