The players

Traffic-quality company that scores every traffic source with the TQI Score; publisher of The Arbitrage Desk.

ClearTrust's click-fraud and invalid-click protection for advertisers who pay per click.

ClearTrust's ad-quality and malvertising protection for publishers.

Independent Australian domain parking and marketplace platform owned by Trellian.

Research firm whose 2023 report exposed where Google's search partner ads were really appearing.

Ad-intelligence suite that lets marketers see which ads and landing pages competitors are running.

Search-feed platform named by trackers and trade guides as an RSOC provider; publishes little about itself.

Ad-tech marketplace that supplies search and native ads to mobile publishers, phone makers and telecom operators.

Competitive-intelligence tool for native, push and pop advertising at a lower price point.

Start-up bought by Google in April 2003 whose technology and AdSense name became Google's contextual ad business.

The company behind Ask.com, for years a large search-to-search arbitrage operator, closed by IAC on 1 May 2026.

Tracker for performance marketers offered self-hosted or in the cloud at a flat price.

Independent US domain parking company popular with domain investors; it ceased operating on 31 January 2026.

Go-to-market security company; owns the click-fraud tool ClickCease and sells traffic vetting to feed platforms.

Ad tracker launched in 2021 with ready-made integrations for search arbitrage feeds such as Tonic, System1 and Sedo.

Perion's search-monetisation unit, which supplied Bing ads to publishers, apps and extensions.

Israeli toolbar maker that earned search-ad money by changing users' default search; merged into Perion in 2014.

US traffic-monetisation platform whose Crossroads portal gives media buyers access to search feeds.

Ad verification company; one of the vendors Google lets advertisers use to pre-screen search partner sites.

Private ad company offering search feeds and tools that turn display and native traffic into search clicks.

US government consumer-protection agency (listed here as a regulator) whose rules on deceptive ads cover arbitrage.

The largest domain registrar; its Afternic and CashParking services earn ad money from parked and unbuilt domains.

The source of most search-ad money, and the rule-maker whose policy changes can remake search arbitrage overnight.

Bot-detection company, formerly White Ops, known for exposing large ad-fraud botnets.

Trade association of the online ad industry; publishes standards and the main US ad revenue report.

Barry Diller's holding company, owner of Ask.com until it closed its search business in 2026; now trades as PPLI.

Dot-com era metasearch company (Dogpile, WebCrawler) whose search business System1 bought for $45 million in 2016.

Ad verification company taken private by Novacap in December 2025; also a Google search-partner pre-screen vendor.

Small listed US ad-tech firm that earns mostly from Yahoo and Google ads shown on its own and partner sites.

German web-hosting group that owns Sedo and decided in 2025 to sell it after parking revenue collapsed.

Early web directory and pay-per-click network that lost most of its revenue overnight when Microsoft left in 2003.

UK click-fraud prevention company, formerly PPC Protect, covering paid search and paid social.

Seattle firm that bet on type-in domain traffic in 2004, sold the names to GoDaddy in 2015, now does call analytics.

US industry body that writes the standard definitions of invalid traffic and audits measurement companies.

Contextual ad network built on Yahoo and Bing search demand, sold to a Chinese consortium for $900 million in 2016.

Owner of Facebook and Instagram, and the most widely used place to buy clicks for social-to-search campaigns.

Privately held native ad network with a large footprint outside the US, widely used by affiliate and arbitrage buyers.

Microsoft's search-ad business: the second big source of feed ads, and the engine behind Yahoo's search results.

US local-news app with its own self-serve ad platform, popular with native and search arbitrage buyers.

The other big native recommendation network; it bought Teads in 2025 and now trades as Teads (TEAD).

The company that invented pay-per-click search ads and the syndicated search feed; bought by Yahoo in 2003.

Team Internet's domain parking platform, which earns money from visitors to unused domain names.

Israeli ad-tech group whose search business, CodeFuel, was built on Microsoft Bing until the 2024 changes.

Visual discovery platform where people plan purchases; a smaller source of clicks for social-to-search buyers.

Israeli company whose content sites and search-feed pages are a common sight in social-to-search advertising.

Tracking, attribution and automation platform for media buyers, with built-in conversion APIs for the big ad platforms.

US native ad network that connects performance advertisers to recommendation widgets on publisher sites.

The largest domain marketplace and a major parking and search-feed platform, put up for sale by IONOS in 2025.

Long-running traffic monetisation platform for domain portfolio owners, registrars and web hosts.

Maker of Snapchat; its ad platform is a secondary source of clicks for social-to-search buyers.

The best-known listed search arbitrage company: buys traffic itself and runs a partner network on Google ads.

The largest native ad network; its recommendation boxes on news sites are the classic native-to-search source.

London-listed owner of Tonic, ParkingCrew, Zeropark and Voluum, rebuilding after Google ended ads on parked domains.

Automation tool that launches and manages campaigns across native and social sources from one dashboard.

Short-video app whose ad platform is a fast-growing place to buy clicks for social-to-search campaigns.

Team Internet's platform that lets media buyers turn paid native and social traffic into search-feed revenue.

Click-fraud and invalid-traffic prevention for advertisers, owned by ASX-listed Adveritas.

Industry programme that certifies ad companies against fraud, malware and piracy.

Dutch group that runs dozens of small search-engine brands and says it is one of the largest Google search partners.

One of the best-known campaign trackers for performance marketers; owned by Team Internet Group.

The third feed: an old search brand whose syndicated ads have become the fallback as Google tightens its rules.

Self-serve ad network selling pop and domain-redirect traffic; part of Team Internet since the 2020 Codewise deal.