Demographics are extrapolated from user panels and multiplied by traffic numbers gleaned from embed codes and presumably ISP data.

Continued below image of search results page.

The search function is primarily targeting ad buyers, just because no one online is willing to pay for anything except ads promoting more monetized mediums, but it is free for anyone to use after creating a Quantcast account.

There are any number of other reasons you might want to use a search service like this. I might be a nonprofit organization, for example, organizing an event that's particularly relevant to a certain demographic group. In that case, making sure I know what some of said group's most popular websites are could prove quite valuable. Asking some people is a good idea too, but a little Quantcast help could be a good first step.

Demographic information can be a touchy subject outside of the ad world, see for example Hillary Clinton's offensive assertion today that she's likely to fair well in the election because non-college educated white people like her best. None the less, though, demographics better engaged with than hidden from.

Room for Improvement

It's not clear how extensive Quantcast's demographic panels are. The company says it gathers this data from "several million" web users. That's great, though I'd like to see what percentage of those millions fall into the different populations they track.

Geographic filtering would sure be great, too, though then we're likely talking about making the pie even smaller and less accurate.

One of the biggest shortcomings of services like Quantcast is that they tend to limit themselves to estimating US traffic. The internet is global, the ad market is too, and some global engagement with geographic filtering seems like a big, open field.

The search here really is just for numbers. It would be awesome to see these demographics integrated into content searches. Quantcast's competitor Compete recently made their data available to users of the Ask.com search engine. This allows searchers to get a feel for the traffic numbers and trends of any site they find search results on. That's pretty handy.

Finally, the ability to filter by traffic trends would be really nice. As you can see from the screenshot above, many of my top search results were sites with falling traffic. What if I wanted to see sites that were growing in total or growing increasingly popular with my target demographic?

Despite its relatively rudimentary beta status, this new offering from Quantcast looks good. It should prove valuable to ad buyers and others and will undoubtedly increase Quantcast's profile online.

But in recent years, that has changed. Alexa now faces competition from Compete, which launched a similar public service in 2006 (our coverage), and from Quantcast, which was founded in 2005. Both of those companies gather data from numerous outside sources and their rankings are generally seen as more accurate than Alexa's.

"In recent months we've heard from our Alexa users that understanding Internet usage beyond Alexa Toolbar users was increasingly of interest," wrote Alexa in the announcement of their rankings overhaul. Recent months? The inaccuracy of the toolbar-based rankings has been discussed for years, which is why we think this might be too little, too late for Alexa.

Beyond the problem of public perception, Alexa also still displays their data in non-standard ways. The hard-to-understand pageviews per million, reach per million, and rank are not easily compared to other data sources, which makes Alexa's information less useful than it could be, even if it is presumably now more accurate.

Historical data on Alexa is currently only available for the past 9 months while the company recalculates old data with its new ranking algorithm.