Numbers below are illustrative and representative of this engagement type. The subject is anonymized, and every figure sits inside published benchmark ranges.
The situation: one list, two audiences
The marketplace held 34,000 contacts, roughly 28,000 buyers and 6,000 sellers, and treated them as one audience. A buyer looking for a deal and a seller worried about listing fees got the same newsletter and the same announcements. The two sides of a marketplace want opposite things, so a single message could only ever be half-right for half the list.
The result was a flat program. Email click-through ran at 1.4%, below the roughly 2.6% all-industry average from Mailchimp, because most sends spoke to the wrong half of the audience. Sellers in particular drifted: onboarding completion sat at 54%, so nearly half of new sellers never finished setting up a working storefront, and the generic email did nothing to pull them back.
What the data showed: a 1.8% capture rate
The signup form converted at 1.8%, under the ~2% all-forms baseline that BDOW reports and well short of the 3 to 8% band a tuned form should reach. Worse, the form captured everyone into the same single opt-in bucket with no role and no confirmation step, so the list filled with mistyped addresses and contacts the marketplace couldn't tell apart.
That mattered twice. Single opt-in let low-quality addresses through, which dragged engagement and reputation. And without a role flag at capture, there was no way to route a new contact into a buyer journey or a seller journey. Mailchimp's study puts double opt-in at +72.2% opens and +114% clicks over single opt-in, so the capture rebuild was both a list-quality fix and a routing fix.
What we built: role-based lifecycles and clean capture
The lifecycle split into two tracks. Buyers entered a journey built around first purchase, browse recovery, and repeat ordering. Sellers entered a separate onboarding sequence that walked them through listing setup, first sale, and payout, with reminders timed to where they stalled. Each side finally got mail written for what it actually wanted. The structure follows our standard approach to lifecycle automation, just forked by role.
The signup form was rebuilt around double opt-in with a role question at capture, so every new contact confirmed their address and declared whether they were there to buy or sell. Fields were trimmed to keep conversion high, and the confirmation step screened out the junk that had been inflating the old list. This capture work is the core of our list growth service: fewer, cleaner, correctly-tagged contacts beat a bigger undifferentiated list every time.
With roles set at capture, segmentation downstream became automatic. New sellers landed straight in the onboarding track instead of a generic welcome, and the reminders that close the onboarding gap could finally fire against the right people.
The results: a 17-point onboarding lift
Signup-form conversion rose from 1.8% to 4.6%, moving the form from below baseline into the 3 to 8% good band. Email click-through climbed from 1.4% to 2.9%, above the all-industry average, because each contact saw role-relevant mail. Seller onboarding completion rose from 54% to 71%, and buyer repeat orders finished 19% ahead.
| Metric | Before | After | Change |
|---|---|---|---|
| Signup-form conversion | 1.8% | 4.6% | +2.8 pts |
| Email click-through rate | 1.4% | 2.9% | +1.5 pts |
| Seller onboarding completion | 54% | 71% | +17 pts |
| Buyer repeat orders | Baseline | +19% | +19% |
The onboarding lift is the one that compounds. Every seller who finishes setup adds inventory that buyers can order, so the seller track feeds the buyer track. These figures remain illustrative of the engagement, not a guaranteed outcome.
What it means for similar marketplaces: tag the role first
A marketplace that mails buyers and sellers as one list caps its own engagement. The fix isn't more email, it's capturing the role at signup and splitting the lifecycle from there. Double opt-in does double duty: it cleans the list and it gives you the flag that makes role-based routing possible.
The pattern holds for any two-sided model. Clean capture with a role at the door, then two lifecycles that serve opposite needs, and onboarding that closes the gap on the supply side. The Growth retainer covers this scope: lifecycle flows, segmentation, and the capture rebuild that makes both work.