What metrics would you use to evaluate a new WhatsApp feature for advertisers

Problem Statement Description

Product context: Meta is a social technology company; its products include Facebook, Instagram, WhatsApp, Messenger, Threads, Quest, creator tools, and ads. WhatsApp is Meta's messaging platform; its products include private chats, groups, calls, communities, channels, business messaging, payments in some markets, and status updates.

Meta is considering a new WhatsApp feature aimed at advertisers. The feature may help businesses reach, engage, or convert customers through WhatsApp, while still operating within the expectations of a private messaging product where user trust, consent, relevance, and safety are critical.

Your task is to define how you would evaluate whether this advertiser-facing feature is successful. The focus is not on designing the feature itself, but on building a useful metrics framework that could guide launch decisions, diagnose performance, and balance advertiser outcomes with WhatsApp user experience.

You should assume multiple stakeholders: advertisers looking for measurable business results, WhatsApp users who may interact with business messages or ad-driven entry points, Meta teams responsible for monetization and integrity, and product teams responsible for long-term engagement and trust.

The experience should consider:

- What the primary success metric should represent and why it is the right decision-making metric

- How to define the metric precisely, including numerator, denominator, time window, and eligible population

- How advertiser cohorts may differ by size, objective, geography, industry, spend level, or maturity on Meta’s ad tools

- How user cohorts and consent states should affect measurement, especially in a private messaging context

- What instrumentation is required to connect ad exposure, WhatsApp interaction, business response, and downstream outcomes

- What guardrail metrics are needed for user trust, spam, blocking, reporting, opt-outs, latency, and message quality

- How to distinguish feature adoption, advertiser value, user experience, and platform revenue impact

- How the metrics would support launch, iteration, scaling, or rollback decisions

The goal is to demonstrate how you would create a rigorous, privacy-aware measurement approach for a hard-to-measure advertiser product inside WhatsApp, ensuring that growth in advertiser value does not come at the expense of user trust or long-term platform health.