The online social media world remains "beyond regulation" the Leveson report has admitted.
Describing the growth of blogs as "little short of phenomenal", he acknowledged such websites were "entirely unregulated" and this situation was unlikely to change.
"Despite the efforts made to comply with national law, it is clear that the enforcement of law and regulation online is problematic," he said.
More than 20 pages of his report focused on alternative news providers - including Twitter - which, Lord Justice Leveson said, had "completely revolutionised" the media market.
While certain social media sites cooperate with UK law enforcement in cases of obvious criminality, he said control which "might have been possible in an earlier age" can now be "defeated instantly on Twitter or any one of many other social media sites, based out of the UK and not answerable to its laws".
He wrote: "Certainly, the very nature of the internet does not lend itself to regulation.
"It is a global network made up of a very large number of interconnected, largely autonomous networks, operating from many different legal jurisdictions without any obvious central governing body."
But he insisted there was scope for websites to cooperate with UK law enforcement in "cases of obvious criminality".
He wrote: "During the rioting in the summer of 2011, both RIM Blackberry and Twitter worked closely with police and other enforcement agencies to identify those using social media and communications networks to perpetrate or help commit criminal acts.
"In 2011, Lancashire County Council also worked with Twitter to identify and bring prosecutions against individuals suspected of tax avoidance."