If you notice a drop in Tier2 ad revenue, this could be due to a number of reasons. This usually indicates either a shift in traffic quality, or that our advertisers have reduced their campaign bids on one or more of your domain name keywords.
Tier2 keyword settings can be manually optimized using the Master Keywords settings via the Manage Domains page.
Please note that Tier2 ad revenue may fluctuate monthly, seasonally, etc., but revenue should stabilize over time.