In a blog post, the company reiterated that sites that use Yahoo’s web analytics tools are required to explain in their privacy policy that they use web beacons to analyse where visitors go and what they do while on the site, and provide a link to Yahoo’s opt-out mechanism.

The opt-out places a cookie on a web users’ computer which prevents further tracking – provided the user does not delete the cookie.

Yahoo said it reserves the right to audit the sites of its web analytics customers to make sure they are in compliance. “Failure to comply can result in your Yahoo Web Analytics account being terminated,” the company said.

The blog post comes in the wake of a high-profile ad campaign orchestrated by the Consumer Watchdog group, which lampooned Yahoo’s chief rival Google, depicting its CEO Eric Schmidt in an ice cream truck offering free cones to children while at the same time collecting their personal information.

The ad sought to encourage viewers to contact their congressional representatives in support of a proposed do-not-track list that would prevent web companies from monitoring people’s online behaviour.

However, Consumer Watchdog itself was accused of hypocrisy when it was revealed that it used Google’s web analytics package to monitor and analyse the behaviour of visitors to its own site.