Alexa an Amazon.com company is best known as a website that provides information on web traffic to other websites. Today Alexa changes it’s design module with addition of new Features like daily average rank, daily average Time spent, previous day rank and more.
Screenshot of the new website traffic overview page.
Also it have effected some of the websites’ traffic rank. Alexa ranks sites based on tracking information of users of its Alexa Toolbar for Internet Explorer and from integrated sidebars in Mozilla and Netscape.
With change in design and introduction of such features, I think it will also improves the accuracy of the traffic rankings.