GOOGLE'S SEARCH ENGINE
Sponsored links involve people in businesses that bid money using familar/popular keywords. According to how high the bid was, it will get sponsored. You will see this typically in different colors compared to the main links that pop up through google or a link or box image on the side of the website. I sometimes also see them at the very top of the page before Google supplies it's suggestions.
When searching something through Google's page, you will find the actual relevance. It will find keywords through your request and supply sites that best interest your search request, matching your search items to an HTML document with those words.