Google is about to change its Adcenter (again)
The first part is easy: the more visitors you have, the more chance you've got that someone will be clicking on adds, the more money you earn.
The second part is more difficult. A company can buy keywords, but the price of them depends on several things. Is you website a 'quality-website' (runs fast, gets a lot of links) then you pay less than if you have a 'minor' website.
Google tries to avoid that the less valuable websites still will get more traffic, just by spending a lot of money, so a kind of quality control.
Every change Google makes in its quotationsystem has got huge consequences. There are thousends of SEMs for whom the main activity is ranking their clients in Adwords. Every time Google makes a change, these SEMs have to change their strategy.
Now this happened again. Google recently announced that it wants to change the Adwords quality score. The quality was now going to be calculated at the moment a search is performed, but at the same time historical data, like the click-through percentage, will still play a big role.
Tagcloudeurope baidu news spain russia research street view yahoo apple funny twitter google google wave china microsoft sea video business search engine strategies social media images ses google earth searchcowboys smx interview streetview seo analytics mobile blogger viral website google tools android search search engines advertising gmail marketing