Revenue leaks are the silent killers of e-commerce profitability. They're not dramatic — no alarm goes off when they happen. They're the slow, steady drip of money leaving your business through gaps you didn't know existed.
After analysing hundreds of e-commerce stores, here are the five most common revenue leaks we see:
1. Misconfigured UTM Parameters
This is the most common and most damaging. When your UTM parameters are inconsistent (utm_source=facebook vs utm_source=Facebook vs utm_source=fb), your attribution data fragments. You can't see the true performance of a channel if it's split across three different labels in your analytics.
The fix: Audit every active campaign's UTM parameters. Create a naming convention document. Use a UTM builder tool that enforces consistency.
2. Over-Attributed Organic Traffic
When tracking breaks — a missing UTM, a redirect that strips parameters, a customer switching devices — the session defaults to "direct" or "organic" in your analytics. This inflates organic's contribution and makes your paid channels look worse than they are.
The fix: First-party tracking with persistent visitor IDs that survive across sessions. Cross-device identity resolution. Regular audits of your "direct" traffic for patterns that suggest paid sources.
3. Retargeting Cannibalisation
Your retargeting campaigns are likely taking credit for sales that would have happened anyway. A customer who added to cart and was going to come back tomorrow gets a retargeting ad, clicks it, and purchases. The ad platform claims the conversion. You think retargeting has 10x ROAS when the incremental lift is much smaller.
The fix: Run holdout tests. Exclude a small percentage of your retargeting audience and compare conversion rates. You'll often find the true incremental value of retargeting is 30-50% of what's being reported.
4. Discount Code Leakage
If you've ever offered a discount code, there's a good chance it's on a coupon aggregator site. Customers who were about to purchase at full price find your code on Honey, RetailMeNot, or a Google search for "[your brand] discount code." You've just given away margin to someone who was already converting.
The fix: Use unique, single-use codes tied to specific campaigns. Monitor where your codes appear. Consider affiliate-only codes that aren't publicly searchable.
5. Broken Post-Purchase Attribution
Most stores stop tracking at the "thank you" page. But understanding what happens after the first purchase — repeat purchase rate by acquisition channel, lifetime value by first touchpoint, which channels bring back buyers vs one-time purchasers — is where the real optimisation happens.
The fix: Connect your attribution data to your customer lifetime value data. Track not just first purchase attribution, but which channels produce your highest-LTV customers. Invest in the channels that bring profitable long-term customers, not just the cheapest first orders.
The Compound Effect
Any one of these leaks might cost you 5-10% of revenue. Combined, they can easily represent 20-30% of lost potential. The fix isn't complicated — it's just visibility. Once you can see the leaks, plugging them is straightforward.