Content.ad Publisher Domains are grouped into two separate Tiers. Domains in both tiers are continuously reviewed and monitored for traffic quality and performance.
Tier 1: Domains with a long-standing history of consistent, good quality traffic.
Tier 2: Generally smaller or new domains whose traffic may not match that of Tier 1.
CPC minimums are slightly higher for Tier 1 and lower for Tier 2.