Pin Point Demographics for Facebook Ads
1)When you scroll down on Quantcast you will see the search bar appear in the top right corner. Simply type in your keyword and wait a second or 2.
2)You will get a list of sites that are all quantified, and that all have enough traffic to get full demographics on.
3)There is also a "see all" link in the bottom right corner of the drop down list where you can see every site that is quantified for that keyword as well as which sites have hidden their demographics.
Using this method I am always able to get pin point demographics and geographic locations for my Facebook Ads that I run for myself.
Enjoy
Richy