04-17-2008, 10:44 AM
Bad news for Alexa manipulators - Alexa rankings are now based on traffic data from outside data sources in addition to data from Alexa Toolbar users. 
full announcement: http://www.alexa.com/site/company/announcement
Quote:In recent months we've heard from our Alexa users that understanding Internet usage beyond Alexa Toolbar users was increasingly of interest. Ask and you shall receive!
We listened to your suggestions, and we believe that our new rankings system is much closer to what you asked for. We now aggregate data from multiple sources to give you a better indication of website popularity among the entire population of Internet users...
My site's ranking has changed. Was it wrong before?
Your ranking wasn't wrong before, but it was different. Alexa toolbar users' interests and surfing habits could differ from those of the general population in a number of ways, and we described some of those possible differences on our website. While the vast majority of sites' rankings were unaffected by such differences, we've worked hard on our new ranking system to adjust for situations in which they could matter.
The new rankings should better reflect the interests and surfing habits of the broader population of Web users.
full announcement: http://www.alexa.com/site/company/announcement