The second revolution has to do with what is technically referred to as "impressions". Impressions are the number of times a PPC advert is displayed on a webpage. An impression means that the advert has been served and is available to the surfer to click.

Impressions have a direct impact on the earnings of a PPC company. The more impressions a PPC company can serve to its audience, the more the literal numbers of clicks. The more the number of absolute clicks, the more the PPC company earns. And this is even without an increase in CTR. This results to a positive spiral. The more the clicks, the more the visitors are channeled to the advertisers' websites. Consequently the advertisers tend to find the particular PPC company effective in driving traffic to their sites.

To achieve this effect, companies looked into ways to increase the number of times surfers see the adverts- impressions.

Before Adword, PPC's jostled to be displayed in websites of high traffic. Websites like AOL and CNN that have millions of visitors per month were targeted to display PPC adverts for a commission. Small websites with hundreds even thousands of visitors were considered insignificant. Then enter Google; they choose to display their ads in each and every website that carried what they refer to as "quality content". Quality content is interpreted by most as referring to informative editorial content as opposed to sales letters, infomercials and plain keyword-based gibberish. Such websites were viable for PPC display in a program called Adsense. This was despite the number of visitors.

This had a near sudden drastic change in the effectiveness of PPCs.

Small websites with less than 200 web pages and a few thousand visitors monthly make up most of the internet. As a result Adword's total impressions increased astronomically beating all its rivals. There was a further positive effect. Often such websites are highly topical and only concern themselves with specific niches like weight loss pills or out-size women's clothing. Consequently the content sensitive Adwords that display on these websites are so relevant to their visitors that CTR automatically shot skywards.

This strategy of involving the small internet guy of the internet resulted to huge increase in earnings without increasing the cost to the advertisers. But most importantly, Google has positioned itself not only as the leading search engine but also the most preferred PPC due to wide reach and affordability. So successful is Adword that Yahoo is in beta testing of a similar concept, and MSN is rumored of being in process of developing "the mother" of all PPCs.