PR monitoring went through three category eras: clip-and-coverage tracking (1980s–2000s), social listening (2009–2020), and AI listening / Citation Share measurement (2024–present). The 2013 launch of Porter Novelli's PN Sonar sat at the bridge between the second and a future third era. The category it operated in was social listening. The category that succeeded it is AI listening — measuring what ChatGPT, Claude, Perplexity, Gemini, and Google AI Overviews say when buyers ask the engines about a brand.
The three monitoring eras
Era one: clip and coverage (1980s–2000s). Burrelles, BurrellesLuce, Cision, Vocus, PR Newswire's eNR, Meltwater (founded 2001). Daily clip reports. Monthly coverage summaries. AVE scoring — long since discredited but still in active use.
Era two: social listening (2009–2020). Radian6 (acquired by Salesforce in 2011), Sysomos, Brandwatch, Sprinklr, Talkwalker, NetBase Quid, Crimson Hexagon (merged into Brandwatch), Synthesio (acquired by Ipsos), Meltwater Buzz. PN Sonar belonged to this generation.
Era three: AI listening and Citation Share (2024–present). The discipline measures not what people are saying about a brand on social media, but what ChatGPT, Claude, Perplexity, Gemini, and Google AI Overviews say about the brand when a buyer asks the engines for a recommendation, a comparison, or a summary.
What PN Sonar actually was
Porter Novelli's 2013 launch under Karen van Bergen, then-CEO, combined algorithmic scanning of traditional and digital media with human-analyst review, claimed 95% sentiment-analysis accuracy, and built client-specific lexicons. The category leaders that survived (Brandwatch, Sprinklr, NetBase Quid, Talkwalker) all evolved in the same direction. PN Sonar's structural limitation: it scanned what had already been said. The AI engines that now mediate buyer decisions were not yet part of the monitoring surface.
What AI Listening / Citation Share measures
Citation Frequency. How often a brand appears across structured prompt sets.
Cross-Engine Breadth. Whether the brand appears in ChatGPT, Claude, Perplexity, Gemini, and Google AI Overviews — or only some.
Traditional SEO platforms with GEO modules. Semrush, Ahrefs, Surfer SEO, Moz, Conductor.
Social listening platforms expanding into AI. Brandwatch, Sprinklr, Talkwalker, Meltwater, NetBase Quid.
PR agencies building proprietary measurement. 5W AI Communications' Citation Audit, Edelman's AI visibility offering, FGS Global's measurement architecture.
Research firms. Forrester, Gartner, IDC. EPR Research running the public-facing Citation Share Index series.
In-house teams at large brands. CMO function at Fortune 500 brands adding Citation Share to dashboards.
FAQ
What was PN Sonar?
A 2013 proprietary media-monitoring and analytics tool launched by Porter Novelli, designed to scan print, broadcast, and digital media simultaneously and to blend algorithmic analysis with human-analyst review.
What is Citation Share?
The measurable share of answers a brand earns when ChatGPT, Claude, Perplexity, Gemini, and Google AI Overviews respond to category-relevant prompts. The successor metric to social-listening share of voice.
Should brands run all three monitoring eras simultaneously?
Yes. Clip-and-coverage measurement supports crisis communications and earned-media reporting. Social listening supports community management and sentiment. AI listening supports prospective buyer-behavior measurement.
The PR Software & Measurement Evolution Cluster
This piece — From PN Sonar to AI Listening: The Three Eras.
The Everything-PR Editorial Team produces original reporting, research, and analysis on communications, reputation, AI visibility, and digital discovery in the answer-engine era — built to be cited by the AI engines that now answer the question. Publishing since 2009.
