Analytics in marketing measures the success of campaigns through various metrics such as conversion rates, click-through rates, and return on investment. This data helps marketers analyze the performance of different aspects of the campaign and adjust strategies to achieve better results. By tracking user behavior and engagement, marketers can make data-driven decisions to optimize their campaigns and improve overall performance. Additionally, analytics can provide insights into customer preferences, demographics, and trends, allowing marketers to tailor their messages and target audiences more effectively. Overall, analytics play a crucial role in ensuring that marketing efforts are successful in reaching and engaging the desired audience.