Native advertising – a form of sponsored content that mimics news articles – has penetrated the news space online and blurred the news-advertising boundary. This chapter traces the historical root of native advertising, summarizes the formats and models of integrating native advertising into news websites, and identifies the limitations and challenges of differentiating native advertising from news in practice, despite prominent research on the effects of disclosure on ad recognition. The disappearing news-advertising boundary highlights a cultural transition from transparency and independence to integration and collaboration within the news organizations. The transition symbolizes a continual power struggle between the autonomous and heteronomous forces in the field of journalism, dominated by the latter. To defend the news-advertising boundary, publishers should disclose native ads explicitly in words and visuals. Audiences should also acquire media literacy and digital literacy to help them differentiate the unique formats, content features, and purposes of native advertising from news.