In reaction to Microsoft’s bid to buy Yahoo, Yahoo ran a trial showing Google ads on Yahoo in the US. Slide 14 in this Yahoo Presentation to their stockholders gives a good explanation to exactly how the test worked (the rest of the presentation also makes for pretty interesting reading).
If Yahoo decided to go [...]

Driving relevant traffic to your website is the most important aspect of PPC management. This means having a very specific set of keywords. However, being more specific with your keyword targeting will lower the overall volume of traffic you can expect to receive. This may lead to missed opportunities and underachievement. Advertising on search engines [...]