I've recently been interested in how Alexa Traffic Rank works. They keep data over time and maintain a website ranking system for millions of websites. At any point, you can see how a particular website is ranked and see changes through time. For grins, here is the Alexa page for my domain.

At some point a few months ago, my site had a ranking of about 3,600,000. So according to Alexa, there were 3.6 million other websites that were more important than mine. Oh well.

But in the past few weeks, my ranking has gone crazy. My overall site rank is now somewhere above 220,000 (the current 1-week average says 220,201, but it used to be higher, so the assumption is my actual "right now" ranking is higher than 220,000). Anyway, my Traffic Rank improved more than 10x. What does that mean?

Apparently, not much. The most important detail is how Alexa gathers traffic data. They do so when users install the Alexa toolbar inside their browser, and it silently gathers web surfing data over time. So for starters, we're looking at a cross-section of all internet users - namely, only the people who have this toolbar installed (and that means only Internet Explorer users, so the cool Mac and Firefox users don't count).

This raises some important questions. How much does the Alexa user community represent all internet users? Does my site really "matter" if Alexa says it does? Contrast this ranking system with Google's Page Rank and an important difference pops up. Page Rank is a function of website relationships (site A points to site B, that's a relationship), and has nothing to do with what a user does (or what their browser choice is). That is, Page Rank works off of the website content itself, whereas Alexa Traffic Rank works off what users click. Presumably, you could have a website with nothing on it (literally a blank page), but if enough Alexa users click on that website name it would receive a high Traffic Rank. So what would that mean? You could have a Page Rank of 0 (really low) with a Traffic Rank of 200 (really high) for a website that has absolutely no value to the world. I'm tempted to devise a plan to drive traffic to blank web page with the sole aim of skewing Alexa ranking data.

So while it's exciting to see my Alexa rank jump way high, it doesn't seem to mean much.