Social media has become a valuable information source that creates opportunities for users to share their comments about a product or service, establishing powerful electronic Word-of-Mouth conversations that may have an impact on purchasing behavior. The study aims to 1) study consumers’ perceptions towards the usefulness of electronic Word-of-Mouth with respect to three factors, i.e. online information quality, online information credibility, and consumers’ attitude towards online information; 2) examine the influence of online information usefulness on online information adoption; and 3) examine the influence of online information adoption on consumers‘ purchase intentions. This study used an online survey to collect primary data from 200 Thai and 200 Indonesian millennial internet users. The result indicates a relatively distinctive result between Thai and Indonesian consumers, as Thai consumers focus mainly on their attitudes towards online information when they consider the usefulness of online information. On the other hand, Indonesian consumers focus on both their attitudes towards online information and the credibility of online information. Nonetheless, both groups share similar traits in other respects. Online information usefulness has an impact on online information adoption, while online information adoption produces a further impact on consumers’ purchase intentions.