Digital Marketing ROI, Social Media Platform Effectiveness and Content-Platform Engagement Matrix for Indian Consumer Brands

India's digital advertising market, valued at ₹57,800 crore in FY2024 and growing at 22% annually — now accounting for 52% of total advertising spend compared to 21% in 2019 — represents the fastest structural media shift in Indian marketing history. The pandemic-accelerated adoption of digital media consumption across India's 759 million internet users, the dominance of short-video content through Instagram Reels and YouTube Shorts (India is YouTube's largest global market and Instagram's second-largest), and the maturation of performance marketing measurement infrastructure have collectively transformed digital marketing from an experimental 'test and learn' budget line to the primary customer acquisition and brand-building investment for Indian consumer brands. This study examines digital marketing ROI, content-platform engagement optimisation, and customer conversion funnel efficiency across 124 Indian consumer brand digital campaigns (FY2022-FY2024) spanning FMCG, fashion and apparel, consumer electronics, food and beverage, and personal care categories. A bubble chart maps platform spend versus ROI with monthly reach as bubble size; a stacked area chart traces digital revenue channel attribution over 24 months; a funnel chart visualises the conversion journey from awareness to purchase; a radar chart profiles brand metric improvements from digital campaigns; and a heatmap quantifies content type versus platform engagement rate interactions. The Wharton collaboration contributes the viral content analysis framework and the social transmission research methodology for understanding digital word-of-mouth dynamics in Indian cultural contexts.