Web traffic monitoring and rankings service Alexa (a division of Amazon) has revamped its ranking protocol. The San Francisco-based measurement firm said that it would be moving away from releasing
data based solely on users of the downloadable Alexa toolbar, to ranking sites based on info from "multiple sources."
Alexa announced the changes in a blog post on Thursday, noting
that some users would notice significant changes in their rankings. Although the service has been popular with smaller sites (with unique visitors or page views that don't qualify for inclusion with
larger services like Nielsen Online or comScore), critics like TechCrunch's Duncan Riley had long argued that Alexa's reliance on data from toolbar users skewed the results and created biased
rankings. One bias, for example, was that the toolbar was unavailable for users of Apple's Mac computers.
As a result of the changes, Alexa rankings data that dates beyond the previous nine
months will no longer be available, but the company said has ongoing plans to recalculate the historical info.
--Tameka Kee