One hacker/malware writer of the DNSChanger malware has pleaded guilty. Only two out of the six have been extradited to the US, so far, to be charged. Valeri Aleksejev, one suspect, has now pleaded guilty and is looking at 25 years in prison, with the possibility of having to pay back up to $7M to victims. Deportation is probable as well.
When hackers change DNS settings, they have the ability to lead the victim(s) to other sites through redirects. Redirects can be used for fraudulent purposes, such as boosting affiliate sales, getting search traffic, etc.
The six suspects in this case effectively manipulated this method and other methods, and “were able to manipulate Internet advertising to generate at least $14 million in illicit fees.”