A mid-tier English-language news publisher serving readers across India and Singapore had been running passive AdSense monetization for four years before migrating to a Pub Clarity managed Prebid setup with five bidders. Over the first quarter post-migration, average eCPM lifted 34% with no change to ad layout, content workflow, or AdSense relationship.
The publisher in this case study operates a daily news site serving English-language readers across India and Singapore. Monthly pageviews at the start of the engagement were approximately 6.8 million, distributed roughly 70% mobile and 30% desktop. Traffic sources were organic search (61%), direct (24%), and social referral (15%). Editorial output was a daily volume of 40–60 articles across politics, business, and culture sections.
Ad monetization at the start was AdSense-only — five ad slots per article (one above-the-fold leaderboard, two in-content rectangles, one below-the-fold leaderboard, one sidebar 300×600), no header bidding, no sticky, no outstream. Average eCPM across the network at the time of migration was $0.78 with monthly revenue of approximately $5,300. The publisher had explored header bidding twice before, both attempts abandoned because the operational complexity outweighed the team's capacity.
The decision to engage Pub Clarity was made on the basis of the managed-service model. The publisher wanted yield lift without committing internal headcount to ongoing header bidding operations. The conversation began in late February; the production rollout completed by mid-March.
Bidder selection started with a shortlist of nine candidates based on the publisher's geo mix (India and Singapore), content vertical (English-language news), and traffic source profile. After two weeks of bid-density analysis against the publisher's historical AdSense inventory characteristics, the shortlist was narrowed to five: two global SSPs with strong APAC presence, two regional SSPs with India-specific demand, and one demand-source aggregator that brought aggregated long-tail demand.
Configuration choices that mattered: bidder timeout was set at 1500ms global with 800ms overrides for the two slowest bidders during the first two weeks (relaxed to 1200ms after performance stabilized). Price granularity was set to dense buckets above $1.00 and standard buckets below to match the demand mix. UserSync was registered for all five bidders with consent gating; the publisher's site is GDPR-relevant due to Singapore traffic, so TCF v2 consent was hard-gated before any UserSync fire.
GAM line items were created at four priority tiers: existing AdSense at standard, header bidding bidders at one tier above AdSense (so they compete fairly), AdSense backfill below header bidding (so AdSense fills when no header bid clears), and house ads at the lowest tier. Key-values were configured per Prebid's recommended naming convention (hb_pb, hb_bidder, hb_size, hb_format) with line items at $0.05 granularity above $1.00.
Week 1 post-launch: revenue was 12% above the pre-launch baseline. The header bidding fill rate was modest (38%) because the bidders had not yet developed a sense for the publisher's inventory characteristics, but average per-bid CPM was significantly above AdSense baseline.
Week 2: revenue 19% above baseline. Header bidding fill rate climbed to 51%. Two of the five bidders showed inconsistent response times; we adjusted their timeouts and floor strategy.
Weeks 3–5: revenue stabilized at 28–32% above baseline. Header bidding fill rate reached 67% across slots, with the two strongest bidders accounting for 64% of all winning bids. We activated dynamic floors on the above-the-fold leaderboard, lifting eCPM on that slot by an additional 9%.
Weeks 6–13: revenue settled at the 34% lift average. Quarterly review identified two underperforming bidders that were paused; we replaced them with one new bidder in the eighth week, no net change to bidder count.
The most important takeaway from this migration: bidder count does not drive yield. Five well-configured bidders outperformed the publisher's previous attempts that used nine and twelve bidders respectively. The previous attempts failed because timeout windows were too tight to capture the slowest bidders, GAM line-item structure did not match Prebid granularity, and UserSync was firing before consent was resolved.
A second takeaway: floor strategy matters more than most setups acknowledge. Dynamic floors on the above-the-fold leaderboard captured an additional 9% on a single slot. Floor strategy on the other four slots was static; we will revisit floor configuration during the next quarterly review.
A third: GAM line-item structure must align with Prebid granularity. The publisher's previous attempts both ran Prebid at finer granularity than GAM had line items to match. The result was bids that won the Prebid auction but lost to AdSense at the ad server because no matching line item existed. We rebuilt the line items at $0.05 granularity above $1.00 and $0.10 below; the alignment alone accounted for an estimated 6–8% of the total lift.
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