QuantCast is an ‘open internet ratings service’, useful for both advertisers and publishers. Advertisers can find reports on the audiences of millions of web sites while publishers can ensure their sites are represented accurately by adding the QuantCast tracking code on their websites.
It’s a free service, and their are several aspects of their reporting that I think makes the service quite useful especially if you want to sell advertising on your website.
For example, take a look at the data QuantCast has for Soccerlens.com. It’s not a lot of information – Alexa does a much better job of telling you where the traffic is coming from (see the Soccerlens.com data) – however for ‘quantified websites (sites that add the tracking code), it’s a far more accurate representation of the audience than what Alexa offers.
Comparing to my own stats, QuantCast is fairly accurate for tracking unique visitors and the percentage of US audience.
What about you guys? Are you using QuantCast on your blogs? Do you use QC as part of your profiling process when researching blogs to buy ads from / get links from?