A 'click' is a term that is no longer just any other ordinary word in the English dictionary. Grammatically it has shifted from a verb to a noun and in the world of the Internet; it now means 'money'. Pay per click advertising is one of the simplest forms of advertising in terms of setting the ad campaigns up. However, achieving success with this model completely depends on the structure of the website and the way it present itself to a first-time visitor.
Ads can be generated or as the term now goes 'populated' in two different ways. The first one is where search queries fed into a search engine by the user triggers off a whole bunch of ads to suit the context of the search query used. The second one is where active websites embed these money-generating ads on their website which also keep changing on a periodic basis to tie in with the existing content of the website.
So, if a visitor or customer visits say a movie review site that uses the 'selective' ad feature, the visitor might actually end up buying a DVD of the movie on liking it and generate money for your site by 'clicking' on one of the relevant ads that talk about stores that sell that DVD online. This is the moment that all advertisers wait for. That true moment of joy when a visitor becomes a potential buyer and the website officially records what is commonly referred to as its first 'conversion'.