A trend you will notice with the ideas on this site is they originate from post-purchase flows – Review Reminders being one.
By post-purchase flows, I mean the actions you can take after a customer has purchased.
The reason why post-purchase engagement is important is because business owners care about metrics such as churn, life-time value, etc. So, if you build products that improve these metrics, the more chances of success you’ll have with getting your first sale and beyond.
That said, a postcard re-engager is a product idea that’s very similar to the review reminder above. We’re pretty used to email receipts and email re-engagements, but what if you, as a business owner, have access to a customer’s actual address? e-commerce store owners come to mind here.
Imagine sending a postcard or a letter to your customer to remind them that you exist. You can even send them a coupon to get them to purchase again from your store, or visit your location.
Small warning, there might be some things to consider here since we’re now dealing with physical addresses and the mailing and spam laws here, but there might be something we can do here.
Building an MVP to test the idea
How do you even build something like this?
lob.com exists to tap into using postcards (or any mail) programmatically.
Next, use Zapier to connect Shopify to Lob.
For Shopify, it makes sense: these are e-commerce stores where customers expect to get a package, so they must share their addresses as part of checkout.
The flow could be — automatically send a postcard to a user after X amount of days after the purchase. It could be a postcard that is a discount or a giftcard, to encourage another purchase on your store. Remember to add a delay between customer purchase and sending a postcard.

Postcard Re-Engager
What if you could reminder customers who've purchased that your business exists through a medium that's nostalgic and physical?