The Nike website was hijacked on Wednesday, redirecting browsers to a site demanding "global justice".
The sports giant has now regained control of its site but for a few hours it unwittingly directed visitors to the web pages of an Australian group called S11, based in Melbourne.
The group says it is a coalition organising protests against the September meeting of the World Economic Forum in Victoria.
Nike said it had updated its security procedures to try to stop the hijacking happening again. No customer information was lost when the site was redirected it said.
Under investigation
Network Solutions, the company looking after the Nike domain, said it was investigating how the hijack, or i-jack as it is sometimes known, happened.
Usually, when websites are hacked, the pages are defaced or replaced with pornography.
Instead, the unidentified hackers behind the i-jack sent people to an anti-capitalism website.
In the past, Nike has been criticised by fair trade campaigners for the low wages the company pays to workers making its shoes and sportswear.
S11 said it did not know who redirected the Nike traffic, why or how it was done. But it thanked Nike for sending lots of visitors its way.
Nike is only the latest organisation to lose control of its website.
Owner occupier
Several companies have suddenly found that someone else has got control of their domain name.
Organisations such as the World Wide Web consortium, Emory University and Solid Oak Software have all briefly had their domains hijacked.
In most cases, lax procedures at the registrar of the domain name have been blamed.
Registrars hold records of who owns which domain name and share the information to ensure there is only one owner of each name.
The ownership of the internet.com name was changed when a forged fax was sent to Network Solutions - the company that maintains one of the largest registers of website owners.
Old contacts
Early reports indicate that similar trickery was used to briefly change ownership of the Nike website.
The i-jackers passed control of the website to a UK-based domain registrar called Frugal Names.
The owners of Frugal Names, an Edinburgh-based, UK company called FirstNET Online Management, noticed the switch and tried to tell Nike about it.
Unfortunately, the Nike webmasters listed in public databases as contacts for the site have left the company making it hard for FirstNET to pass on its warning.