The article examines the impact of influencers and opinion leaders on sales through the lens of the transformation of the consumer journey and the restructuring of managerial metrics in digital commerce. The relevance of the study is determined by the crisis of trust in traditional advertising, the fragmentation of media consumption, and the expansion of social commerce, where purchases are increasingly completed within social platforms via seamless shopping mechanics and algorithmic feeds. The purpose of this work is to systematize the psychological and economic mechanisms of influence, conceptualize the collapse of the sales funnel, and formulate a strategic framework for increasing ROI through advertising with bloggers. The scientific novelty lies in the synthesis of the Source Credibility Model, Parasocial Interaction Theory, and Elaboration Likelihood Model with market data for 2024–2026, as well as in substantiating the shift from reach-based evaluations to a financially oriented logic of LTV, CAC, and ROAS grounded in AI-based attribution and predictive scoring. The key findings demonstrate that micro- and nano-influencers in niche markets generate denser trust and a higher return on budget, and that the sales funnel is evolving into a cyclical community model in which content, social proof, and purchase form a self-sustaining loop that requires authenticity risk management and advanced multichannel analytics. The article is of practical value for marketers, e-commerce owners, and executives responsible for sales growth and the effectiveness of advertising investments.