Calculation of Alexa Rankings

I don't understand how these are calculated

[ChrisK]

I subscribe to the Alexa database which displays rankings of sites that I visit, and the current ranking of my own site.

I don't understand how these rankings are calculated, which visitors they include, how often they are updated etec. etc.

Can anyone advise please?

[mbauser2]

Those of you using Alexa to estimate relative traffic numbers (something I've been meaning to look into, myself) might find Jacob Nielsen's "Compute Your Own Web Traffic Rank" worth a read. His explanation of Zipf distributions could be relevant.

http://www.useit.com/alertbox/relativeranking.html

In fact, searching his site for "Zipf" will find a whole set of articles on traffic curves.

[dauction]

mbauser..

interestinglying enough after reading the link you provided..
http://www.useit.com/alertbox/relativeranking.html

using his formula ..he states his site ranks roughly in the top 10,000..

just for kicks look at your alexa ranking for his site..

10,416!

I also use alexa ...but only as a tool..just as as you would any other tool..combine it with other information for a more comprehensive look

[mbauser2]

Alexa changed their ranking system today. Subdomains are now consolidated into the main domain's ranking. Yahoo.com and MSN.com are the new top 2. Google drops to #5.

And my personal site jumped up about 250,000 places. Jeez.

[ThaddeusB]

At least the new system makes more sense, even if it does make my efforts to find the top sites void. :)

Incidentally, hanmail.net (daum.net) is still #3.

[vitaplease]

thanks for the update info mbauser2,

As you observed it does look as if the consolidation effect of main and sub urls made the changes.

I wonder if Alexa will ever integrate Google popularity data and vice versa.

[ThaddeusB]

apparently we still won't see it :)

[cheemo]

Alexa's homepage has a link to their top 500 sites. I don't know if thats been posted, but I remember users were interested back when this post was going around and that's why I brought it back.

There are a surprising number of non-english sites, also Gator's site eguard.com is #26....That makes me ill.

[richlowe]

Question: it seems the consensus is Alexa is fluff. Is it a good idea to ban it? If so, what's the name of the 'bot for robots.txt?

I know, that's 2 questions, but...

Richard Lowe

[edit_g]

You can't really ban it from ranking you. That data is based on people with the Alexa toolbar installed visiting your site. The spider is probably coming from the Internet Wayback project- also run by Alexa and owned by Amazon.

[DiAMOndDavE]

Alexa's top 500 list DOES appear skewed towards Japanese and Asian web sites. Does anyone know of a site that shows equivalent US/European data?
DiAMOndDavE