Google has acted to stop the use of metered paywalls on news sites, describing the enabler as a 'loophole'.

Sites were previously able to detect visitors 'browsing incognito' on its Chrome product, using the information to count visits.

Google says that "as every web user should have the right to browse the web privately if they wish", this enabler should be stopped.

What was describes as the 'FileSystem API loophole' allowed sites to detect users and stop them from avoiding metered paywalls. Typically 'metered' or 'soft' paywalls give readers access to a limited number of free articles before they are asked to sign up. Among users are Nine's Sydney Morning Herald and The Age sites.

Google acknowledges the changes will impact publishers, but questioned the effectiveness of metred paywalls. Partner development manager, news and web partnerships Barb Palser described the model as "inherently porous" and says private browsing is one of several tactics used to manage cookies and reset the meter count. She suggested publishers consider reducing the number of free articles which can be viewed before logging in, requiring free registration to view any content, or hardening their paywalls.