Getting a top organic ranking in Google can drive a huge amount of customers to a website, resulting in large profits.
Break the rules and this traffic stream can be turned off overnight.
Recently, GoCompare.com, a large car insurance comparison site that most of us see in TV adverts every day, was apparently hit by a penalty moving them from number 1 to page 7 for the search term "car insurance".
Google has yet to comment on the story but most search experts agree that the site appears to have been given a penalty for buying links, a tactic against the Google guidelines.
Normally a site being penalised in Google isn't major news (it happens every day) but in this case Hitwise has done some research into the effects of the penalty and offered some interesting statistics.
Apparently before the sudden drop in rankings, 1 in 6 visitors to GoCompare.com found the site by searching for "car insurance".
Afterwards the traffic dropped 87%.
Traffic to Confused.com has increased a staggering 77% in recent weeks as it gained the number 1 ranking.