This study examines how social, cultural, and political symbols in YouTube videos influenced viewer engagement and trust during Taiwan's 2024 election. Through analyzing 1973 videos, we found cultural symbols generated the highest engagement levels, while social symbols were most effective for trust-building. Content incorporating multiple symbol types demonstrated enhanced effectiveness across both metrics. Our findings extend Media Richness Theory by demonstrating how symbols serve as information-rich cues that enhance content complexity while facilitating user comprehension in algorithmic environments. The research also advances Social Presence Theory by showing how symbolic elements strengthen perceptions of human connection in digital interactions, directly affecting trust formation. These insights contribute to understanding how symbolic communication shapes political discourse on digital platforms. By bridging communication theory and IS research, this work provides valuable guidance for content creators, political communicators, and platform developers seeking to enhance engagement and build trust in increasingly complex digital information environments.