Inconsistent Volume + Low-Intent Cohorts = Yahoo Throttle

Yahoo's filters reward steady cadence and penalize erratic sends. If engagement slips (esp. from co-reg or older inactives) while volume spikes, Yahoo treats your mail as "gray"—throttling or bulk-foldering even clean lists.

• Volume spikes: big batch jumps reset reputation and trigger delays.
• Low engagement: inactives + mixed-intent sources drag down sender score.
• Complaint sensitivity: keep visible spam complaints well below ~0.2%.

Heavy tracking strings in visible link text, image-heavy layouts, inconsistent "From" names, and lack of a one-click unsub inflate risk. Keep anchor text semantic and reduce above-the-fold link clutter.

1. Isolate: send Yahoo/AOL on their own campaigns.
2. Stabilize: cap increases to ~20%/week while watching KPIs.
3. Schedule: consistent daily/near-daily cadence beats sporadic blasts.

Suppress Yahoo readers inactive > 60 days. Start with your most active cohort, then gradually re-include warm segments as metrics normalize.

Use recognizable From names, match subject + preheader to content, keep a one-click unsub prominent, and avoid surprise frequency changes.

A/B a plain-text-lean intro vs. design-heavy. Shorten visible link text (semantic, not UTM soup). Confirm SPF/DKIM/DMARC alignment and monitor Yahoo Postmaster for errors.