By now you've heard about
what's new over at
Alexa. In addition to the traffic metrics you already use, we've begun serving up Demographics, Clickstreams, and measures of Search Traffic for virtually any site on the web. Understanding the demographics can be a bit daunting at first, so in today's post we'll explore what the demographics data are all about, and then we'll have some fun seeing who goes where on the web.
The secret to understanding the demographics is this: for any given category, a site's demographics score is the
ratio of that category's representation in the site's audience, to that category's representation in the total population of folks who use the internet.

That's a mouthful, and I learn best from simple examples, so let's explore the meaning of that statement with a goofy scenario. Let's pretend that the internet is used by just two types of people: the Greens and the Reds. And let's say that the entire population of people who use the internet consists of just six Greens and eight Reds, like in the picture at left.
Now let's imagine a hypothetical site on our tiny internet: ilovegreen.com, and let's suppose that the audience for this site consists of the three Greens and two Reds shown in the picture at right.

What would
Alexa say about the popularity of ilovegreen.com among the demographic of Green users? Well Greens visit the site at a rate of 3-to-2, while they are represented on the web in general at a rate of just 6-to-8. If you like math, you can divide these rates to see that Greens visit ilovegreen.com at a proportionally higher rate than they surf the web in general; in this simple example, Greens are over-represented in ilovegreen.com's audience by exactly a factor of two. In other words, ilovegreen.com is popular among Greens. (Don't worry: if you don't like math, you'll see below that we publish our demographics data as a handy graphic which captures all the raw numbers in an intuitive way.)
Remember, the fact that this hypothetical site scores high with Greens doesn't tell you about the
absolute number of Greens who visit the site. What it does tell you is that Greens are represented in the site's audience to a much greater extent than they are represented out there on the web in general. In that sense, this site is preferred by Greens.
Now that we've gotten the hard part out of the way, let's have some fun. First, let's check out some sites for which we might already have pretty good guesses as to their demographics. In the charts below, a red bar pointing to the left means a category is proportionally under-represented in a site's audience; a green bar pointing to the right means a category is over-represented. So how about
ufc.com, the homepage of the Ultimate Fighting Championship?

No surprises here:
ufc.com is overwhelmingly preferred by young men. That is to say, men between the ages of 25 to 34 are strongly over-represented in the audience of
ufc.com, compared to how they are represented on the internet at large. For the most part, these young men have college educations (or at least they're working on it), they tend not to have kids, and when they're surfing the web for news about, say, Yoshihiro Akiyama (one of the biggest mixed martial arts stars in Asia) they're doing it from home.
Now how about a site on the opposite end of the spectrum? Here are the demographics for
nordstrom.com:

I know my sister spends a lot of time there, and apparently she's not alone. The audience for
nordstrom.com contains college-educated, 25 to 34 year old women to a much greater extent than does the general internet population. And they tend to do their shopping from work! I'm sure it's on their lunch breaks...
A couple of more no-brainers, while we're at it. What do you suppose is the age distribution for folks who frequent the official website the U.S. Social Security Administration?

You guessed it: the users of
ssa.gov skew toward web-surfers in their golden years. And what about folks at the other end of life's journey? Well, you might guess that their parents do some browsing over at
landofnod.com, a retail site specializing in kids' furniture. So what do our data have to say about
landofnod.com's audience?

Sure enough, they've got kids.
But enough confirming what we might already have guessed.
Alexa's all about web discovery, right? Let's do some discovering. One thing folks certainly use the internet for is to find... each other. Three of the big players in the internet dating game are
match.com (Alexa rank 359),
chemistry.com (Alexa rank 6,517), and
plentyoffish.com (Alexa rank 410).
Now imagine you're searching for that special someone, and you want to stand out among all the riff-raff. Check out the gender distribution of
match.com:

Men and women are represented at
match.com in almost equal proportion to their representation on the internet at large. For a high traffic site, that means there are plenty of men and plenty of women -- so if you're a man trying to stand out among men, or a women trying to stand out among women, you're out of luck. But never fear!
Alexa's here to help you,
ahem, improve the odds.
Compare the gender distribution of
chemistry.com:

to that of
plentyoffish.com:

Compared to the general internet population, women are over-represented at
chemistry.com, while men are over-represented at
plentyoffish.com. So if you're looking for boys, go where the boys are. And if you're looking for girls, go where the girls are!
Perhaps this wasn't what you had in mind when we said that
Alexa's data gives you a competitive edge, but then again, who's complaining?