Made-for-advertising (MFA) describes websites built to sell advertising impressions rather than to serve readers. Their operators buy visitors cheaply, usually through clickbait ads on social networks and content recommendation widgets, then show each visitor far more ads than a normal page would carry, keeping the difference between the cost of the visit and the programmatic revenue it produces. The label exists because such sites pass most automated checks. The traffic is largely human, placements are viewable and the content is rarely offensive, so conventional fraud and brand safety filters let the impressions through.

How the arbitrage works

The working definition was published on September 26, 2023 by a consortium of the Association of National Advertisers (ANA), the American Association of Advertising Agencies (4A's), the World Federation of Advertisers (WFA) and the Incorporated Society of British Advertisers (ISBA). According to the ANA, MFA sites usually exhibit some combination of five traits: an ad-to-content ratio at least twice the internet average, for example 30% or more on desktop; rapidly auto-refreshing placements, autoplay video and slideshows that force clicks through multiple ad-laden pages; a high share of paid traffic with little organic audience; generic, syndicated or templated content; and poorly designed template websites. The ANA identified buying traffic as the primary cost of running such a business, and aggressive monetisation as the way to recover it.

A simplified illustration shows the arithmetic. An operator pays 5 cents for a click from a social feed. The visitor lands on a 20-page slideshow carrying six ad units per page and views eight pages, generating 48 impressions before any refresh. At a $1.50 cost per thousand impressions (CPM), those impressions earn 7.2 cents, a margin of 2.2 cents per visit. Across 100,000 bought visits a day, that is roughly $2,200. The model breaks the moment CPMs fall below the cost of traffic, which is why MFA supply swells when advertiser budgets peak.

Operators also hide the model from inspection. The ANA's complete report of December 2023 noted that Jounce Media found many MFA sites removing ads for visitors arriving directly, then flooding the page for visitors referred by social media, search engines or content recommendation. Production costs have collapsed with generative tools: DoubleVerify's Fraud Lab traced a 200-domain network, which it named AutoBait, producing clickbait articles for about $2.25 each.

Where it sits in the transaction

Nothing in the bid request marks a site as MFA. Most such properties are technically legitimate sellers: they publish an ads.txt file naming authorised sellers, and their inventory enters open auctions through supply-side platforms (SSPs) as OpenRTB requests identifying the domain and page. Classification is layered on from outside, by data vendors and by the platforms themselves.

On the sell side, SSPs filter at the source. Sharethrough removed MFA sites from its off-the-shelf deals and from custom private marketplaces created after July 1, 2023, using Jounce data; MFA had made up 9% of that deal inventory, according to Adweek. Teads declared its inventory fully MFA-free in March 2024, and Taboola applied Jounce's detection to its Taboola Select network on October 2, 2024.

On the buy side, demand-side platforms (DSPs) apply pre-bid segments that remove classified domains before a bid is placed. DoubleVerify launched MFA avoidance on September 14, 2023 and split the category into High, Medium and Low tiers in early 2024, scoring sites on ad density, traffic sources and content creation practices. Integral Ad Science (IAS) classifies ad clutter sites as MFA when they run arbitrage operations. Attention vendor Adelaide's floor for Amazon DSP combines MFA exclusion with a bottom-decile attention filter. Private marketplaces, inclusion lists and supply path optimisation sit alongside these tools.

From made for AdSense to made for advertising

The acronym is older than programmatic trading. In the 2000s, MFA meant made for AdSense: thin pages built to harvest clicks on Google's contextual ads. A WebmasterWorld thread from July 2008 debated where the line fell, and Search Engine Roundtable returned to the classification question in December 2010. After Google's Panda update of February 2011, SEO practitioners warned that layouts pushing content below ads carried ranking risk.

The programmatic version took its current name around 2021. According to Chris Kane, founder of Jounce Media, speaking at an AdExchanger event in 2023, arbitrage sites accounted for about 5% of open web auctions in 2020, 15% in 2021, 20% in 2022 and roughly 30% by mid-2023.

The ANA turned the issue into a budget line on June 19, 2023. Its study of 21 member companies, covering $123 million of spend and 35.5 billion impressions between September 2022 and January 2023, found MFA sites took 21% of impressions and 15% of spend. The complete report in December 2023 found only 36% of post-transaction budget reaching valid, viewable, measurable, non-MFA impressions. According to the same report, global MFA spend was recalculated at about $10.1 billion, 15% of a $67.3 billion open web market excluding connected TV, down from the $13 billion first estimated. The consortium definition, drafted with Kane and Rocky Moss of DeepSee, followed in September; the 4A's preferred "made for arbitrage". IAB Australia added its own guidance in June 2024.

Why buyers care

The cost is diversion as much as waste. "MFA publishers siphon ad spend that media buyers would otherwise deploy to reputable publishers," Kane said when Teads announced its clean-up. Integral Ad Science has put annual advertiser waste on MFA inventory at about $10 billion.

Performance data points the same way. DoubleVerify measured a 19% year-on-year rise in MFA impression volume in 2023 across more than one trillion impressions, with attention 7% lower for display and 28% lower for video than on quality inventory. The ANA study also found that MFA inventory generated 26% more carbon emissions than non-MFA supply, and that curated deals were not immune: according to TAG TrustNet, an average of 14% of private marketplace spend contained MFA inventory.

Limitations and disputes

The definition is deliberately loose. "Some combination" of five traits leaves each classifier to set its own thresholds. "The term 'Made for Advertising' has created significant confusion within the industry," Jack Smith, chief product officer at DoubleVerify, said in September 2023. DoubleVerify's own method excludes sites carrying many ads if they still draw high direct and search traffic, which means two vendors can grade the same domain differently. PPC Land noted concerns about transparency in vendor criteria as early as 2024.

Nor is the category universally unwanted. The ANA's complete report conceded that MFA value is somewhat subjective, and that some direct response and performance marketers may find it useful. MFA traffic can be entirely human, which makes it a quality judgment rather than a validity judgment.

Measurements diverge because denominators differ. Jounce's 30% counts auctions. The ANA's 15% counted spend in 2023. The ANA Programmatic Transparency Benchmark, which covers advertisers actively managing quality, recorded MFA between 0.4% and 0.6% throughout 2025. IAS reports rates by channel. None of these figures is interchangeable.

Enforcement has lagged pledges. Adalytics reported in March 2024 that ads from major brands were still transacting on sites meeting MFA definitions through Google, Amazon DSP, Magnite, PubMatic and others, and TripleLift was among the exchanges observed despite its stated commitment to blocking MFA. Amazon said it proactively blocks MFA inventory; a Google spokesperson told Adalytics that Google prohibits publishers from using disruptive or deceptive ad serving purely to generate revenue. Because MFA domains rotate, lists ingested statically fall behind.

Not the same as

Arbitrage is the trade; MFA is the property. PPC Land's arbitrage explainer notes that an MFA site can draw organic traffic and arbitrage can route to legitimate publishers.

Invalid traffic concerns whether an impression was seen by a real person. MFA inventory usually passes that test.

AI slop describes mass-produced synthetic content. It overlaps heavily with MFA but is defined by authorship rather than monetisation.

Pink slime refers to partisan or automated sites posing as local news, a political category that may or may not carry MFA traits.

Recent developments

Measurement has become more granular through 2026. IAS reported on July 9 that mobile web display carried a 2.0% MFA rate against 0.5% on desktop during 2025, and later that the channel generated 71.9% of measured MFA impressions.

On July 28, TAG, the ANA and Fiducia found that 88% of AI slop inventory was also classified as MFA, and that MFA exposure had risen to 1.1% in the first quarter of 2026, the first meaningful increase in the benchmark. The slop was graded premium more than 70% of the time and cost $7.08 per quality-adjusted thousand impressions, against $6.15 for clean supply. The benchmark's second-quarter release in August put the share of spend reaching quality impressions at a record 45.1%, according to Fiducia.

Supply-side scrutiny widened in September, when BidSwitch opened Adalytics bidstream audits to its supply partners at no cost. On September 15, Chrome added ad density and ad count metrics to its public user experience dataset, giving buyers a browser-sourced measure of one MFA trait, as of September 2026 without thresholds attached.

Timeline

  • July 2008 - WebmasterWorld members debate what qualifies a site as "made for AdSense"
  • December 2010 - Search Engine Roundtable revisits how to classify made-for-AdSense sites
  • February 2011 - Google's Panda update prompts warnings about ad-heavy layouts
  • 2020 - Arbitrage sites account for about 5% of open web auctions, by Jounce Media's estimate
  • 2021 - The made-for-advertising label enters use; share rises to about 15% of auctions
  • September 2022 to January 2023 - Data period of the ANA programmatic transparency study
  • June 19, 2023 - ANA reports MFA sites took 21% of impressions and 15% of spend
  • July 1, 2023 - Sharethrough begins excluding MFA from off-the-shelf deals and new custom deals
  • September 14, 2023 - DoubleVerify launches MFA measurement and pre-bid avoidance
  • September 26, 2023 - ANA, 4A's, WFA and ISBA publish a joint MFA definition
  • December 2023 - ANA complete report finds 36% of budget reaching quality impressions and resets MFA spend at $10.1 billion
  • February 13, 2024 - DoubleVerify announces tiered MFA categories
  • March 2024 - Adalytics reports brands still transacting on MFA sites; Teads declares its inventory MFA-free
  • June 2024 - DoubleVerify reports a 19% rise in MFA impression volume for 2023; IAB Australia publishes MFA guidance
  • October 2, 2024 - Taboola partners with Jounce Media to screen Taboola Select
  • 2025 - ANA benchmark records MFA exposure between 0.4% and 0.6% each quarter
  • July 2025 - Integral Ad Science classifies AI-generated ad clutter sites running arbitrage as MFA
  • March 4, 2026 - DoubleVerify publishes its AutoBait investigation into a 200-domain network
  • May 27, 2026 - ANA reports MFA exposure of 1.1% for the first quarter of 2026
  • June 10, 2026 - Adelaide brings an attention floor with MFA exclusion to Amazon DSP
  • July 9, 2026 - IAS reports a 2.0% MFA rate on mobile web display against 0.5% on desktop
  • July 28, 2026 - TAG, the ANA and Fiducia find 88% of AI slop inventory also classified as MFA
  • August 6, 2026 - Second-quarter benchmark puts quality-reaching spend at 45.1%
  • September 2026 - BidSwitch opens Adalytics bidstream audits to supply partners
  • September 15, 2026 - Chrome publishes ad density and ad count metrics in CrUX

Summary

Who. Operators of arbitrage websites create the supply; SSPs, exchanges and DSPs transact it. The ANA, 4A's, WFA and ISBA wrote the consensus definition with input from Jounce Media and DeepSee, while DoubleVerify, Integral Ad Science, Jounce, DeepSee and Adalytics classify or audit it.

What. A website built primarily to monetise bought traffic through dense, frequently refreshing ad placements on generic or templated content. It is a quality classification applied from outside the bid request, not a fraud category, and each vendor draws the line differently.

When. The idea dates to made-for-AdSense sites of the 2000s. The programmatic label emerged around 2021, the ANA quantified it on June 19, 2023, and the joint definition followed on September 26, 2023.

Where. Open web display and video bought through open auctions and, to a lesser degree, private marketplaces, with the highest measured concentration on mobile web display. Traffic is sourced from social platforms and content recommendation widgets.

Why. Each MFA impression that clears the auction diverts budget from publishers producing original work. The sites are built to look good on viewability, invalid traffic and brand safety metrics, which is why a separate label, and separate filters, became necessary.