The paid media glossary.

Customer acquisition cost (CAC) is the total sales and marketing spend needed to win one new customer, found by dividing that spend over a period by the number of customers acquired in it. Paid CAC counts ad spend only; blended CAC adds tooling and team cost.

Return on ad spend (ROAS) is the revenue generated for every dollar spent on advertising, calculated as ad-attributed revenue divided by ad spend. A 4:1 ROAS means four dollars of revenue for every dollar spent. It measures revenue efficiency, not profit.

Cost per lead (CPL) is the average ad spend required to generate one lead, calculated by dividing spend by the number of leads captured. It is an early-funnel efficiency metric, and a low CPL means little if those leads never become pipeline.

Pipeline ROAS measures ad spend against the sales pipeline it generates, the value of the opportunities created, rather than just immediate revenue or lead count. For B2B with long sales cycles, it is the truest early read on whether paid media is working.

A marketing qualified lead (MQL) has shown enough interest, such as a demo request or content download, for marketing to pass it to sales. A sales qualified lead (SQL) has been vetted by sales as a genuine opportunity worth pursuing. The gap between them is where most B2B ad budget leaks.

Multi-touch attribution distributes credit for a conversion across all the marketing touchpoints a buyer interacted with, rather than crediting only the first or last click. It is essential in B2B, where a single deal can involve many touches across weeks or months.

First-touch attribution gives 100% of the credit for a conversion to the first interaction a buyer had with you; last-touch gives it all to the final interaction before they converted. Each answers a different question: first-touch shows what creates demand, last-touch shows what closes it, and neither alone reflects a multi-step B2B journey.

Data-driven attribution (DDA) uses an account's own conversion data to distribute credit across the touchpoints on the path to conversion, rather than applying a fixed rule like first- or last-click. It is now the default conversion attribution model in Google Ads, which has deprecated the older rule-based models except last-click.

An attribution window, or lookback window, is the period after an ad interaction during which a resulting conversion is credited to that ad. Meta's default is a 7-day click window, meaning a conversion counts if the person clicked within the previous seven days; shorter windows or view-through windows credit fewer or different conversions.

Demand capture converts buyers who are already looking for a solution, for example through Search ads on category keywords. Demand generation creates awareness and interest before that search happens, for example through LinkedIn and content. You cannot capture demand that does not exist yet.

Quality Score is Google Ads' 1-to-10 rating of how relevant and useful your keywords, ads, and landing pages are. A higher score lowers your cost per click and improves ad rank, so it directly affects how far each dollar of budget stretches.

Target CPA (tCPA) is a Google Ads Smart Bidding strategy where you set the average cost you are willing to pay per conversion and Google bids automatically to hit it. Set it too low and the algorithm chases only the cheapest conversions, so it acts as an optimization instruction, not a spending cap.

Performance Max (PMax) is a goal-based Google Ads campaign type that serves across all of Google's inventory, Search, Display, YouTube, Gmail, Maps, and Discover, from a single campaign. Instead of keywords, you give it assets, audience signals, and search themes, and its AI optimizes toward your conversion goal across channels.

Retargeting (also called remarketing) shows ads to people who already interacted with you, most often visitors who came to your site but didn't convert. Because the audience is already warm, it is usually far cheaper per result than prospecting, and on Google you can keep retargeting a visitor for up to 540 days.

Negative keywords are terms you exclude so your ads don't show for irrelevant searches. They protect budget from off-intent clicks, for example blocking "free", "jobs", or a competitor's brand. They can be applied at ad group, campaign, or account level, and now to Performance Max as well.

Placement exclusions (or negative placements) stop your ads from serving on specific websites, apps, app categories, YouTube channels, or videos you don't want. They are how you keep Display and Performance Max off junk inventory like games and low-quality apps. PMax respects account-level and MCC-level exclusions, but not campaign-level ones.

The Meta Pixel is a snippet of tracking code on your website that records what visitors do, so you can build retargeting audiences, measure conversions, and optimize Meta ad delivery. It is the behavioral backbone of Meta advertising, and it is increasingly paired with the Conversions API for server-side tracking.

The Conversions API (CAPI) sends conversion events to Meta directly from your server, rather than only from the browser through the Meta Pixel. It recovers measurement and optimization signal lost to browser restrictions and ad blockers, and it runs alongside the pixel, not instead of it.