This article investigates the moderating role of review helpfulness on the effects of online review content and linguistic style matching on new product sales. Using data from 105,494 online reviews from a popular website, IMDB.com, following 264 movie releases, the article shows that the impact of review style and content on new product sales is contingent upon review helpfulness. In particular, results suggest that linguistic style matching, positive emotion, and cognitive components of online review content significantly impact new product sales when the reviews are deemed helpful by the readers. These findings collectively suggest that online review research benefits from deeper textual analysis that includes review content and linguistic style compared to traditional methods that rely solely on numerical ratings. Also, review helpfulness plays a critical role in consumer decision‐making considering a rapidly increasing amount of online information is now available to consumers.