Alexa's certified program and pro metrics.
http://www.alexa.com/siteowners/certify
Analytics and Tracking · Audience Measurement · Visitor Count Tracking
Get access to data on 331,102 websites that are Alexa Certified Site Metrics Customers. We know of 34,796 live websites using Alexa Certified Site Metrics and an additional 296,306 sites that used Alexa Certified Site Metrics historically and 16,114 websites in the United States.
Get a list of 331,102 websites using Alexa Certified Site Metrics which includes location information, hosting data, contact details, 34,796 currently live websites and an additional 67,250 domains that redirect to sites in this list. 296,306 sites that used this technology previously and 16,114 websites in the United States currently using Alexa Certified Site Metrics.
Countries
Financial
Group
Region
These are sites that we think might use Alexa Certified Site Metrics in the future because of their similarity to other sites that already do.