Dixons-online.com and dixons-online.co.uk were set up more than a year ago to provide a forum for Dixons customers to post their views on the retailer.
"We are all for freedom of expression but there is a difference between freedom of expression and exploiting a domain name that has very deep links to our company," Dixons said.
The case, which was settled in arbitration, hinged on whether the alternative sites could have confused the public, even though they carried disclaimers disassociating themselves from the retailer.
The ruling will have significant implications for other sites that use disclaimers in an attempt to ward off legal action from the owners of trademarked domain names.
Dixons said it had saved thousands of pounds by referring the case to the domain name body Nominet and the World Intellectual Property Organisation's mediation service, rather than to the courts.
Andrew Horrocks, partner with law firm Barlow Lyde & Gilbert representing Dixons, said it would have been difficult to obtain legal redress against the registered owner of the site, Abu Abdullah, listed at an address in Saudi Arabia, through the UK courts. "We would have had to find out exactly who the owner was and any judgement would have been difficult to enforce," he said.