Monetization Glossary: RPM, CPM, EPC, Header Bidding, Churn, Merchant of Record & More Explained

Plain-English definitions of website and creator monetization terms: RPM vs CPM, EPC, header bidding, ad management partners, fill rate, cookie windows, reversals, merchant of record, churn, paywalls and more.

RPM (revenue per mille): What you earn per 1,000 pageviews or sessions, across everything on the page. Session RPM is the honest number for a publisher: total revenue divided by sessions, times 1,000. A US general-interest blog runs roughly $10-25 session RPM on display ads; finance can be three times that, entertainment a third of it.
CPM (cost per mille): What an advertiser pays for 1,000 ad impressions. One pageview usually carries several impressions, so CPM is always higher than the RPM you actually bank. Ask any network for session RPM, not CPM.
CPC, CPA, CPL, CPI: The four ways performance advertising pays: per click, per acquisition (a sale), per lead (a form fill) and per install (an app). Affiliate offers are almost always CPA or CPL; push and pop networks sell CPC.
EPC (earnings per click): Affiliate commission divided by clicks sent, usually quoted per 100 clicks. It is the only number that lets you compare a 3% commission on a $2,000 product with a 50% commission on a $30 one.
Header bidding: An auction run in the reader's browser before the page loads, letting many ad exchanges bid at once instead of falling down a waterfall. It typically lifts publisher revenue 20-50% over AdSense alone, which is most of what ad management partners like Mediavine, Raptive and Ezoic sell.
Ad management partner: A company that takes over your whole ad stack — demand, header bidding, layout, consent, video — in exchange for a share of revenue, usually 10-25%. Mediavine, Raptive, Journey by Mediavine, Monumetric, Freestar and Playwire are the main ones. They have traffic minimums; that gate is why publishers care about session counts.
Fill rate: The share of your ad requests that actually get an ad. Low fill in a country or format means unsold inventory; mediation and backfill networks exist to raise it.
Viewability: Whether an ad was actually on screen long enough to count (50% of pixels for one second, by the standard measure). Buyers pay for viewable impressions, so sticky units and content-embedded placements earn more than a banner at the bottom of a page.
Core Web Vitals and ads: Ads are the usual reason a site fails Google's speed metrics, mainly through layout shift when a slot loads late. Reserving the exact slot size and lazy-loading below-the-fold units usually recovers the score without losing revenue.
ads.txt / sellers.json: A public file at the root of your domain listing who is authorised to sell your inventory. Missing or wrong entries silently cut demand, because buyers filter out unauthorised sellers. Every network gives you the lines to paste.
CMP and consent: A consent management platform collects the permission European and UK readers must give before personalised ads run. Without one, European traffic falls back to non-personalised ads at a fraction of the price.
Cookie window: How long after a click you still get credit for a sale: 24 hours on Amazon, 30-90 days on most networks, sometimes lifetime. Long windows and last-click attribution decide how much a referral is really worth.
Last-click attribution: The standard affiliate rule: whoever sent the most recent click before the purchase gets the whole commission. It is why coupon sites and browser extensions are controversial — they arrive last.
Reversal / clawback: A commission taken back when the buyer refunds, cancels or is judged fraudulent. A network with a 30% reversal rate pays far less than its headline commission suggests.
Merchant of record: A platform that legally sells the product to the customer and therefore handles VAT, sales tax and chargebacks for you (Gumroad, Paddle, Lemon Squeezy, FastSpring). Costs more than a plain processor like Stripe and removes a real compliance burden.
Churn: The share of subscribers who cancel each month. At 5% monthly churn a subscriber lasts 20 months; at 10% they last 10. Recurring revenue businesses live or die on this number, which is why dunning, annual plans and pausing matter so much.
ARPU and LTV: Average revenue per user per month, and the total a customer is worth before they leave (roughly ARPU divided by churn). Every paid acquisition decision compares LTV with cost to acquire.
Conversion rate: The share of visitors who take the action you get paid for: buy, subscribe, sign up, click the affiliate link. Free-to-paid conversion on newsletters runs 3-8%; on freemium software, 1-4%.
Hard, metered and freemium paywalls: A hard paywall gates everything, a metered one gives a few free articles a month, and freemium leaves some content free forever and gates the rest. Metered earns the most search traffic; hard earns the most per subscriber.
Disclosure and rel="sponsored": Paid content must be labelled for readers under advertising rules in most countries, and paid links must carry rel="sponsored" or rel="nofollow" for Google. Skipping either risks a regulator or a manual penalty, and usually both.
Link insert (niche edit): A link added into one of your existing articles for a fee, rather than a whole sponsored post. Easy money and the single fastest way for a content site to lose search rankings if it is done at scale or hidden.
Rate card: Your published prices for sponsorship: cost per newsletter send, per podcast read, per sponsored post, per banner month. Having one stops you negotiating from scratch every time and is what marketplaces list on your behalf.
Newsletter CPM (per open): Newsletter sponsorships are priced per 1,000 opens, typically $20-60 for a general list and $100+ for a tight professional one. Paid by opens, not sends, so list hygiene pays twice.
Host-read ad: A podcast ad read by the host in their own words. Priced far above a produced spot ($18-50 CPM against $10-18) because listeners do not skip it.
Dynamic ad insertion: Stitching ads into a podcast at download time rather than baking them into the file, so old episodes keep earning and campaigns can be swapped, targeted and capped.
Rewarded video: A mobile ad format where the player chooses to watch in exchange for an in-game reward. The highest-paying ad unit on mobile and the least resented, because it is opt-in.
Ad mediation: A layer that asks several mobile ad networks for a bid and serves the best one. Running a single network typically leaves 20-40% of app ad revenue unearned.
App store cut: Apple and Google take 30% of in-app purchases, dropping to 15% for the first $1M a year (small business programmes) and for subscriptions after year one. Web checkout avoids it where the rules allow.
Sale multiple: What a website sells for, expressed as a multiple of average monthly net profit — typically 30-45x for content sites, higher for SaaS and for revenue that does not depend on one traffic source or one person.
Passive income: Revenue that continues without proportional new work. Display ads and affiliate links on evergreen content come closest; courses and memberships need support, updates and marketing, and are better described as leveraged than passive.
Revenue diversification: Running several unrelated methods so no single algorithm, network or platform can end the business. The practical test: if your largest revenue line went to zero tomorrow, would the site still cover its costs?
Tranco rank: A research-grade ranking of the million most popular websites. Monetizes refreshes each provider's rank daily and uses the change to spot networks and platforms that are growing.