Online porn is a very lucrative business today. Some researcher's web crawler found that porn sites offered free content as marketing strategy for other expensive adult content. A large volume free sites can be used to get new visitor or members. Based on comScore Media Metrix research, there were 63.4 million unique visitors to porn websites in December of 2005, it was 37.2% of the total Internet users. According to John E Dunn from techworld, some researchers were able to buy traffic 49,000 unique visitors from third-party sites just for $161, it shows how easy that for porn webmaster to find audience.
Online porn is also source of malware distribution. What is malware? Malware is malicious software that created to infiltrate computer system, installed without user intention and it can be used to steal important data such as credit card number, user's online bank login and password or it was created to damaged and disturbed user's computer operating system. Malware can be viruses, worms, trojan horses, spyware adware and other unwanted software. That's the reason why porn sites was contained with malware. It can generate cash using illegal ways.
