Library
A working collection.
Every Yewgo assignment lives here once it goes out. Newest first.
Assignment #9 · Deliverability · December 21, 2026 · 5 min
Your authentication is fine. Your audience isn't.
An apparel brand's daily Gmail spam rate went over 0.1% on five days in 30 while its authentication passed. How I read the spikes, why zero complaints in the sending platform meant nothing, what the Feedback-ID header is for, an engaged segment built on opens, six mailbox providers nobody was mailing, and an audit you can run on Monday.
Assignment: Pull 30 days of Gmail spam rate from Postmaster Tools next to your daily send volume. Then find the Feedback-ID header in a recent campaign and count last month's campaign recipients by mailbox provider.
Assignment #8 · Retention · December 14, 2026 · 5 min
Why Black Friday should start early
A hand-dyed yarn brand gives its email list the biggest code of the year in early November and keeps Black Friday weekend to chosen items. Why the early window exists, what a predictable sale costs, the one test inside the plan, and how to lay out your own Q4 on Monday.
Assignment: List every discount you ran in the last 12 months, mark the ones a regular could have seen coming, and keep three at most. Then give your list its biggest code in a short window a few weeks before Black Friday.
Assignment #7 · Retention · December 7, 2026 · 5 min
Black Friday without the discount
An apparel brand ran 30% off sitewide two Black Fridays in a row, and orders in the window still fell 29.5% (count, YoY). This year's offer kept every product at full price and added a gift card at two basket sizes: $20 at $150, $35 at $300. How the rungs were sized from full-price orders, what the card does to basket and margin against a percentage off, and how to size your own.
Assignment: Group a full-price month's orders by value, find the median order and the average item price, and set your first gift rung about one item above the median.
Assignment #6 · Acquisition · November 30, 2026 · 5 min
Sell the sample, then the order
At an architectural products retailer, the ads sold a sample first and the emails carried buyers toward the full order, which came a median of about 25 days later. How I designed each piece, how I measured it, and what to build on Monday.
Assignment: List the worries that stop someone ordering your full product, then check that each one has an ad and a landing page that answer it, and an email that picks it up after the sample.
Assignment #5 · Deliverability · November 23, 2026 · 5 min
Deliverability is a segment decision
A kidney-health supplement brand had 7,393 bounces in one day after its domain went offline. How I read the spike, the engaged and never-engaged segments I built, a 14-day cooldown used in place of suppression, two welcome flows that collided on one list, and an audit you can run on Monday.
Assignment: Pull 90 days of bounces split by mailbox provider and by hard or soft, then check who every campaign and welcome flow sends to.
Assignment #4 · Lifecycle · November 16, 2026 · 5 min
Migrate your ESP without losing revenue
At a large California retailer we moved 9 million profiles from Cordial to Klaviyo in peak Q4 and reached roughly 9 million emails a day in 45 days with no revenue-impacting incident. The order I'd migrate in, how I'd plan the warmup and check the data, which flows to rebuild first, and a checklist for before you set a date.
Assignment: Before you agree to a cutover date, work through the pre-migration checklist and put the warmup on the calendar.
Assignment #3 · Measurement · November 9, 2026 · 5 min
Attributed is not incremental
Abandonment flows look like your best emails because they reach people already close to buying. How I read those reports, a vendor whose credited orders were mostly already in motion, and a simple holdout you can start on Monday.
Assignment: Hold back 10% of abandoned-checkout entrants for two weeks and compare order rates from the store's data, not the email report.
Assignment #2 · Measurement · November 2, 2026 · 5 min
Your GA4 sees 54 cents of every dollar
On one account, GA4 recorded about 54% of the revenue the store took in. Here is how I measured the gap and why no budget moved until our model matched the store within about 2%.
Assignment: Divide 90 days of GA4 purchase revenue by the store's own order revenue. Then split out the orders that never touch the site.
Assignment #1 · Retention · October 26, 2026 · 5 min
The first 60 days decide everything
At the retailer, the first order was 70% of the average customer's two-year value, and the best chance at the rest came in the next 60 days. What the data showed, what I built around it, and three things to check in your own account.
Assignment: Pull last December's first-time buyers and count how many ordered again within 60 days. Do the same for an ordinary month and compare.
Get each one the Monday it goes out.
Every Monday. One thing I learned doing the work.