A partner email program still works best the way Liberty Travel ran this one: a partner collects opt-ins, and the signup triggers an automated series built around a date the subscriber cares about, here the wedding date. What has changed is the rulebook. Since February 2024, Gmail and Yahoo require bulk senders (for Gmail, those sending 5,000 or more messages a day to personal Gmail accounts) to authenticate with SPF, DKIM and DMARC, offer one-click unsubscribe for marketing mail and keep reported spam low (Google says below 0.1%, and never reaching 0.3%). Microsoft’s Outlook.com began enforcing similar rules on May 5, 2025, for domains sending more than 5,000 messages a day to its consumer addresses. Apple Mail Privacy Protection has also made open rates unreliable, so a series like this one is now judged on clicks, leads and bookings.
The Liberty Travel session
Another strong presentation at the
came from Jason Steele of Liberty Travel. His talk was titled “Email and Complex Partnership Marketing Campaigns.” Liberty Travel brought in partners to run a co-registration (co-reg) program. People who signed up on a partner’s site could also opt in to hear from Liberty Travel. Liberty then sent triggered emails to give that shared audience messages that matched where they were in their plans.
Liberty Travel no longer trades under that name. Its owner, Flight Centre Travel Group, moved the Liberty Travel stores and advisors to its Envoyage brand on July 1, 2025.
Why weddings and honeymoons
Steele’s team picked a big vacation that people tend to plan with a travel agent: the honeymoon. They partnered with two wedding brands, David’s Bridal and TheKnot.com. The partnership gave Liberty Travel three things:
- A younger audience. Engaged couples were a chance to win customers for life.
- Qualified online leads. Leads went to honeymoon specialists, who closed the sales offline.
- A bigger house list. Liberty’s own email list grew with every opt-in.
Both partner brands have changed since then. David’s Bridal went through bankruptcy in 2023 and now has new owners. The Knot is part of The Knot Worldwide, and in October 2026 Reuters reported, citing unnamed sources, that the company was set to buy Zola. Treat that as reported, not confirmed.
How the campaign worked
Everything in the campaign hung on one piece of data: the wedding date each partner collected at signup. That date set off an automated series that sent one email a month for a year.
What the emails covered
Each email was designed to look like the partner site the subscriber came from. That kept the brand familiar and made the email easy to recognise in the inbox. The series included:
- A welcome message
- Budget planning for the honeymoon
- Wedding destinations
- The top 10 honeymoon destinations
(best performing
- Reasons to book early
- Why using a travel agent matters, plus other planning topics
The results
The process ran fully on automation, so it needed no extra staff. Sales from the program earned twice the average profit of Liberty Travel’s other programs and channels.
The session was one of the most practical case studies at the
Running a partner campaign like this today
The core idea still holds up: one date, collected with clear consent, drives a series that ends on its own when the event is over. What has changed is everything around it. Consent, authentication, unsubscribe handling and measurement all face stricter rules than they did when this case study was presented.
| Area | When this case study ran | November 2026 |
|---|---|---|
| Partner opt-in | “Hear from our partners” checkboxes were common | Name the brand that will email. The UK ICO says a vague “selected third parties” consent is very unlikely to count |
| Authentication | Optional for most senders | SPF, DKIM and DMARC are required for bulk senders at Gmail and Yahoo (from February 2024) and at Outlook.com (from May 5, 2025). The threshold is about 5,000 messages a day to each provider’s personal or consumer addresses |
| Unsubscribe | A link in the footer | One-click unsubscribe for marketing mail at Gmail and Yahoo, with opt-outs handled within 2 days. CAN-SPAM requires opt-outs to be honoured within 10 business days |
| Spam complaints | Tracked loosely | Google recommends staying under 0.1% and avoiding a rate of 0.3% or higher |
| Measurement | Open rates | Apple Mail Privacy Protection hides whether a recipient opened an email, so open rates are unreliable. Track clicks, leads and bookings |
| Reading | Mostly desktop | Mostly mobile, often in dark mode, with Gmail’s tabs and image proxy |
Consent and the law
Under CAN-SPAM you can’t hand off your legal responsibility. The FTC says both the company whose product is promoted and the company that sends the email can be held liable. For an email with several advertisers, the advertisers can agree that one of them is the “sender” and handles opt-outs. Each violating email can cost up to $53,088. The FTC set that inflation-adjusted maximum in January 2025, and in September 2026 it confirmed that its 2025 penalty levels stay in force for 2026. If you mail people in the UK or EU, the bar is higher: consent must be specific, and it must name your brand.
Authentication for the sending domain
If a partner’s platform sends on your behalf, the From domain still has to pass SPF or DKIM in alignment and publish a DMARC record. A starting record looks like this:
_dmarc.example.com. TXT "v=DMARC1; p=none; rua=mailto:[email protected]"
Start at p=none so you can read the reports. Move to quarantine or reject once every legitimate source passes.
Cadence and the end date
A monthly email for 12 months is a sensible pace for a purchase planned this far ahead. Today you would add two things. First, send the welcome email within minutes of signup, while the partner brand is still fresh in the subscriber’s mind. Second, stop or switch the series once the wedding date has passed. Honeymoon emails that keep arriving after the honeymoon are the kind that get reported as spam.
FAQ
What is co-registration in email marketing?
Co-registration means a partner’s signup form includes a separate opt-in for your brand. When someone ticks it, their details are passed to you. It’s legal if the consent is clear and names your brand, and if you mail the lead soon after signup. Buying lists dressed up as co-reg is not the same thing and does real damage to deliverability.
Is co-registration still worth doing in 2026?
Yes, if the partner’s audience fits closely, the way engaged couples fit a honeymoon seller. Co-reg leads usually engage less than people who sign up on your own site, so a fast welcome email and early pruning of inactive leads matter. Low-fit, high-volume co-reg leads drive up spam complaints, which can push you above Google’s recommended rate of under 0.1% and toward the 0.3% level it says to avoid.
Who is responsible for CAN-SPAM compliance in a partner email?
Both the company whose product is promoted and the company that sends the email may be held legally responsible, according to the FTC. When several advertisers share one email, they can agree on a single designated sender who appears in the From line and handles opt-outs. Opt-out requests must be honoured within 10 business days, and the addresses of people who opted out can’t be sold or transferred, except to a company hired to help you comply with the law.
Do the Gmail and Yahoo bulk sender rules apply to triggered emails?
Yes. Google’s rules apply to bulk senders, meaning those that send 5,000 or more messages a day to personal Gmail accounts, and they cover triggered messages as well as campaigns. All mail from that domain then has to meet the authentication rules. Marketing messages, including automated nurture series like this one, also need one-click unsubscribe. Transactional messages such as booking confirmations don’t need one-click unsubscribe.
How should you measure a date-triggered email series now?
Use clicks, form fills, calls to specialists and bookings, and tie them back to the email that drove each one. Apple Mail Privacy Protection preloads images, which records “opens” that never happened, so open rates overstate engagement. Google Postmaster Tools shows your Gmail spam rate, which is the number to watch week to week.
Sources
- Google Workspace Admin Help: Email sender guidelines and sender guidelines FAQ
- Yahoo Sender Hub: Sender best practices and requirements
- Microsoft Defender for Office 365 Blog: New requirements for high-volume senders to Outlook.com (April 2025)
- Federal Trade Commission: CAN-SPAM Act, A Compliance Guide for Business
- Federal Register: FTC notice on 2026 civil penalty amounts
- UK Information Commissioner’s Office: Guidance on consent and direct marketing
- Envoyage: Liberty Travel is now Envoyage (FAQ)