The text discusses how product marketers can use private beta periods to shape their marketing strategies. Before the beta begins, it's essential to understand the goals of the product team and the beta plan, including the schedule, user selection criteria, and desired feedback or data collection. The marketer should incorporate their positioning into the invitation to test it with beta users and evaluate customer reactions. This can involve A/B testing messaging, validating the hierarchy of benefits used in marketing messaging, and assessing how well the product communicates its value to customers. During the beta, marketers should set accurate expectations for their product by identifying limitations and addressing pain points, and use this information to refine their messaging. Additionally, betas provide an opportunity to reevaluate the target audience, choose the appropriate announcement level and channels, and identify key customers for testimonials. By making the most of private beta periods, product marketers can improve their planning, positioning, and overall marketing strategy.