Social problems theory has yet to fully address the impact that new communication technologies are having on the claims-making process. This article examines the emergence of the blogosphere as a cultural phenomenon that provides claims-makers with a powerful new public arena to advance social problem claims. Using Stephen Hilgartner and Charles Bosk's (1988) public arenas model of social problem construction, blog-generated problem claims are examined to analyze how Internet driven social problems compete for public attention. Findings suggest that blogs make the claims-making process more efficient, offer expanded carrying capacity compared to traditional arenas, and provide outsider claims-makers with greater opportunity to have a voice in social problems construction. Still, only a small number of blogs have become recognized as claims-making arenas; they still rely on traditional principles of selection; and bloggers face the same competition for mainstream media attention as claims-makers using traditional arenas.