Online retail giant Amazon has rejected using Phorm's Webwise service, which tracks users' activities online and sends them targeted, context-sensitive advertising.
Amazon is one of the largest, most successful online sites to block Phorm. Its decision to stop the intrusive online tracking service from using the Amazon website could mark a turning point, say commentators.
Jim Killock, executive director of The Open Rights Group, which campaigns for the rights of online users, says, "This is a blow for Phorm. Its business model has serious problems. A lot of website owners do not wish to give their consent to have their website's traffic intercepted. Phorm's model assumes it is okay to use people's personal or business information."
LiveJournal, mySociety and Netmums have also blocked Phorm.
Earlier this week, the European Commission launched proceedings against the UK concerning the use of Phorm. EU Telecoms Commissioner Viviane Reding said, "We have been following the Phorm case for some time and have concluded that there are problems in the way the UK has implemented parts of EU rules on the confidentiality of communications. I call on the UK authorities to change their national laws and ensure that national authorities are duly empowered and have proper sanctions at their disposal to enforce EU legislation on the confidentiality of communications."
How to block phorm
Website owners can find instructions on how to block Phorm on BT's site.
One user commenting on the Open Rights Group site suggested users run the Firefox browser with the Adblock Plus add-on. He said it makes users "pretty much immune from 99% of all adverts ever reaching your screen; targeted or not. It also prevents advertisers stealing your precious bandwidth and spoiling your web browsing experience".