In 2014, researchers at Harvard Law School published a study that should have alarmed anyone who relies on the web for business. They analyzed links in Harvard Law Review articles and found that approximately 50% of URLs embedded in those articles no longer pointed to their original content. Half. Gone.
The study focused on legal citations, but the phenomenon it documented is universal. Links decay. Pages move. Domains expire. Content gets restructured. The web is not a library with permanent addresses. It is a living system where things change, break, and disappear constantly.
For most websites, a broken link is a minor inconvenience. A reader clicks, hits a 404 page, shrugs, and moves on. But for affiliate publishers, a broken link is something else entirely: lost revenue that nobody notices.
What makes affiliate links different
A regular hyperlink connects point A to point B. An affiliate link connects point A to point B through point C, D, and sometimes E. The typical affiliate link passes through:
- The publisher's redirect (often a tracking or cloaking layer)
- The affiliate network's tracking domain (Awin, CJ, Amazon, TradeTracker, etc.)
- A network-specific redirect that appends tracking parameters
- The merchant's landing page or product page
Each step in that chain is a potential point of failure. A regular link has one dependency: the destination page. An affiliate link has three or four. This makes affiliate links structurally more fragile than ordinary web links.
Each step = potential failure point
If the Harvard study found 50% link rot for simple URLs over a decade, the rate for affiliate links is almost certainly higher. There is no large-scale academic study on affiliate link decay specifically, but the mechanics make the conclusion hard to avoid.
The five causes of affiliate link rot
Affiliate links don't break randomly. They break for specific, recurring reasons that follow patterns across the industry.
1. Product discontinuation. This is the most common cause. A publisher reviews a product, links to it with an affiliate tag, and the product gets discontinued six months later. The merchant removes the product page or redirects it to a category page that strips the affiliate tracking. The link technically "works" (it returns HTTP 200) but no longer points to a purchasable product. The publisher's commission opportunity vanishes.
2. Merchant URL restructuring. When merchants redesign their websites or migrate to new platforms (Magento to Shopify, for example), product URLs often change. Old URLs may redirect, but redirects frequently strip affiliate tracking parameters. The publisher's link still sends traffic, but the network can no longer attribute the sale.
3. Tracking parameter degradation. Affiliate networks use URL parameters to identify publishers and track conversions. These parameters can break in surprisingly mundane ways: a merchant's CDN strips query strings, a redirect drops the referral ID, a URL encoding change makes the tracking token unreadable. The link works for the visitor but fails for the publisher's wallet.
4. Redirect chain breakage. Networks occasionally change their tracking domains, update their redirect infrastructure, or modify how deep links are constructed. When a network migrates from one tracking domain to another, publishers with thousands of links built on the old domain may find them all broken simultaneously. This can happen without any notification.
5. Merchant program closure. Merchants leave affiliate networks. They close their affiliate programs entirely. They switch from one network to another. When this happens, every link a publisher built to that merchant through that network stops generating commissions. The links may still send traffic to the merchant's site, but the tracking is dead.
Why this is underreported
Link rot in affiliate marketing is not a new phenomenon. Publishers have dealt with broken links since the industry began. So why does it remain a largely unquantified problem?
Three reasons.
First, broken affiliate links often don't look broken. A regular broken link returns a 404 error. A broken affiliate link frequently returns HTTP 200 with a "product not found" page, or redirects to the merchant's homepage, or lands on a category page. Standard link-checking tools report these as healthy links. They are not.
Second, the financial impact is invisible. When a link breaks, nothing happens. There is no error email, no dashboard alert, no notification from the network. The publisher simply stops earning commissions from that link. In a portfolio of hundreds or thousands of affiliate links, a few going silent is noise in the monthly report. You cannot miss revenue you do not know you were supposed to earn.
Third, nobody in the chain is incentivized to measure it. Affiliate networks do not track or report link health metrics. Merchants do not notify publishers when product pages change. Industry analysts measure total affiliate spend, but not the gap between what publishers should earn and what they actually receive. The leak exists in the space between these perspectives.
The scale of the problem
The global affiliate marketing industry generated over $20 billion in revenue in 2024, with projections pointing toward $31 to $40 billion by 2031. Even conservative estimates of link rot's impact suggest meaningful numbers.
Consider a mid-size affiliate publisher with 500 product reviews, each containing an average of 3 affiliate links. That is 1,500 links. If general web link rot research suggests roughly 5% of links break per year (a conservative reading of the available data), that is 75 links breaking annually. If each working link generates even modest revenue, the cumulative loss adds up quickly.
Now multiply that across the hundreds of thousands of affiliate publishers operating globally. The industry has never quantified this aggregate loss, but reasonable estimates place it in the range of $200 to $400 million per year. Not because any single publisher is losing millions, but because small, silent losses across a massive number of publishers compound into an enormous sum.
A structural problem, not a personal one
It is tempting to frame link rot as a maintenance issue. Publishers should check their links more often. They should update old content. They should have systems in place.
This framing misses the structural reality. Affiliate links depend on infrastructure that publishers do not control: merchant product catalogs, network tracking systems, and redirect chains managed by third parties. A publisher can do everything right and still lose revenue because a merchant restructured their URL scheme over a weekend.
The problem is not that publishers are careless. The problem is that the affiliate link ecosystem has no built-in mechanism for detecting and communicating breakage. When a link breaks, the information asymmetry favors everyone except the party losing money.
This is a systemic issue. It deserves systemic attention, starting with accurate measurement of the problem's actual scope.
What comes next
The first step toward solving any problem is acknowledging it exists and understanding how big it is. The affiliate industry has grown rapidly, but its infrastructure for link health monitoring has not kept pace. Publishers are building their businesses on a foundation of links that degrade over time, with no standard tools to detect that degradation.
That gap represents both a real cost to publishers and an opportunity to build something better. The technology to monitor affiliate links at scale exists. The question is whether the industry will adopt it before the losses compound further.
This is part of how we think about affiliate infrastructure. Read the broader argument →