One such hacker is 29-year-old Christian Valor, who lectures on Internet security. Mr Valor, who is better known on the Internet as "Se7en", released what he called his "war manifesto" on the Internet just over a year ago and vowed to deliver "genuine hacker terror" to those he found trading in child pornography on the net.
Although an accomplished hacker, who renamed the CIA web page "the Central Stupidity Agency", Se7en is not a malicious hacker, or "cracker" as they are known.
Most hackers do what they do simply because they can, and occasionally to highlight the inefficiencies in computer programmes that are supposedly secure. Crackers will hack into different systems to cause damage or to steal sensitive information.
Se7en's reasons for beginning his crusade are simple: "I had been lecturing on Internet security for a while, and I had been telling people that the amount of child pornography on the Internet that the media was claiming was there was just hype.
"Then one day I got an e-mail with a picture attachment. I opened up the picture and it was a four-year-old being raped by two grown men. I wasn't able to determine who had sent me the picture, so that's what started me off on this whole thing."
While most of the hackers tracking paedophiles are based in the United States, there are some groups in the UK who are also doing their best to stop the illegal trade.
Cotton Ward, features editor at .net magazine, began her own investigation into paedophiles using the Internet and was surprised by the sheer volume of material available.
Reader response to her story in .net led to a regular update in the magazine on sites and organisations dedicated to tracking down paedophiles.
The Internet, as it is used by most people, is mainly made up of World Wide Web pages, text and graphic files combined into pages that are accessible by anyone with a computer and modem. Alongside this run newsgroups, which pre-date the graphics-driven end of the Internet, and Internet Relay Chat, or IRC.
A newsgroup is a computerised mailing list, where all list members receive any message posted to the list by another user. The IRC chat rooms are areas where users can "chat" live to one another using text messages.
Those involved in hunting the paedophiles tend to log in to other computer systems and find out details of the people behind anonymous e-mail addresses and identities.
Once this is completed, the hackers can then go about naming and shaming the offenders. This can involve logging onto a user's machine and leaving a message on the system so that when anyone else logs on they are given a message explaining that child pornography has been deleted from the computer and naming the user who put it there.
One news group that Se7en terrorises receives about 5,000 postings a week. But this number drops dramatically if he is successful in revealing a paedophile's behaviour.
"Every time I nail someone, this figure drops to about 500 messages and stays that way for a few days. Then it gradually starts to pick up again and is soon back to 5,000."
He doubts whether paedophiles will ever be removed from the Internet: "I don't think anything will ever be done about this. It's part of human nature. The Internet is just a slice of life, a cross-section of the population. People do it, it's something that's always going to be there, you can't control it. They'll nail people here and there, but they will never be able to effectively control it."