Africa’s expanding youth population and rapid digitalization present opportunities for innovation and, ultimately, entrepreneurship and economic growth relevant for Sustainable Development Goal (SDG) 8—Decent Work and Economic Growth. However, the role of social media in shaping these outcomes remains underexplored empirically. This study examines how platform-specific social media use influences innovation, operationalized through external search breadth and depth, while considering macroeconomic moderators. Using panel data from 52 African countries from 2009 to 2022 and fixed effects regressions, the study links activities on Facebook, X (formerly Twitter), YouTube, LinkedIn, and Google to innovation indicators such as R&D expenditure, patent applications, and scientific publications. The findings suggest that YouTube use is consistently and positively associated with all innovation indicators, highlighting its role in knowledge diffusion and creative expression. By contrast, X and LinkedIn display neutral or negative effects. High internet penetration alone is not sufficient enough to spur innovation, underscoring the need for enabling macroeconomics factors such as GDP per capita and ease of doing business. This study concludes that visual open-access platforms, supported by education and institutional capacity, are vital for inclusive and sustained economic growth.