Pay-per-click (PPC) advertising involves paying each time a user clicks on your link. This is different from normal search engine results in that your web site does not have to be optimized, but you pay for each user clicking your link as opposed to each click being free as in normal search results. The advantage is that you can pay for top placement, rather than leaving your ranking to the mercy of a search engine's proprietary ranking algorithm. Two such programs are described below.

Overture, formerly GoTo until October 2001, is a paid placement search engine. This means that you can pay to get top placement for the search terms you want.

Overture is also a paid listings distribution network that provides its listings to many other search engines. Overture itself estimates that more than 90 percent of users see its links at their partner search engines instead of at the Overture site.

Google has developed their own pay-per-click program called Google AdWords Select. The AdWords program allows listings to appear in boxes that run along the right-hand side of Google's results page. These are sold on a self-serve basis, which means you can get started almost immediately, as long as you have a credit card.

Rank is determined by a combination of PPC and clickthrough rate. If an ad is irrelevant to users, they won't click on it and it will move down the page. Your relevant ads will rise, at no extra cost to you.