Abstract: With the changes brought by streaming media to the production and consumption of TV series, ordinary audiences’ evaluations of actors have significantly influenced both the creative and industrial fields. This study focuses on how online audiences in the post-traffic era perceive and express actors’ performances. Through discursive practices such as bullet comments and short reviews, they gradually form a lay theory about “what constitutes acting” and “what makes a good actor.” This includes audiences’ preconceptions of actors’ performance levels and their evaluations of performance details, character depth, and sense of authenticity. These discourses on acting reflect the characteristics of online social interaction and digital culture, explaining and expressing audiences’ understanding of good acting and high-quality TV series. The lay theory of performance evaluation represents the formation of a discursive community among audience groups regarding actor evaluation, fostering a positive environment for creative appraisal and extending the social and cultural influence of TV dramas.

Key words:  lay theory, actors, acting skills, bullet comments, TV series