Readership popularity has been an important proxy for the success of many online interactive media. Given the exponential growth of new web properties and the hype of competition among them, attaining and retaining popularity is difficult. One possible approach to this problem is to enhance the competitiveness of web presence by using appropriate web design mechanisms. So far, research in this area has been focused on technological issues or usability studies. Few studies have recognized the importance of media-embedded social scripts or environmental cues in influencing online communication. Drawing on social cognition theories, we identified two important media-embedded characteristics: source credibility and content freshness; and tested their impact to readership popularity in online interactive media. The content analysis result from 100 very popular weblog sites strongly supported our hypotheses. Our findings highlight key web design principles, which may serve to guide the practice of millions of online users and practitioners.