1. An online content evaluation system comprising: a scanning server to scan web sites and to collect metrics for online ads, wherein the scanning comprises: parsing web pages for the web sites, identifying ad beacons from the parsed web pages, determining whether the ad beacons include information identifying the online ads as online ads for a predetermined company, and determining the metrics for the online ads identified as online ads for the predetermined company; data storage storing the metrics for the online ads; and an online content evaluation server classifying online ads, wherein the classifying comprises: classifying the online ads into candidate groups based on the metrics, wherein, for each candidate group, the online ads classified into the candidate group are estimated to be in a same ad campaign; executing a group merging process to merge at least some of the candidate groups and to determine campaign groups at least from the merged groups; and assigning an ad campaign to each campaign group.