Web 2.0 technologies are empowering consumers to co-produce online brand communications and thereby co-create brand meaning. As both consumers and marketers are increasingly using video-sharing websites to showcase their brand communication efforts, viewers of these ads are inadvertently becoming part of the co-production process as they create context around the ads (in the forms of reviews, comments and ratings). The environment in which such online advertisements are viewed has significant effects on consumer perceptions of the ad message, and ultimately impacts the persuasive properties and efficacy of the ad. This study reports on research conducted to test the source effects of consumer-generated advertising. Schlinger's Viewer Response Profile (VRP) is used to assess the impact of three source variables: ad creator, ad popularity and motivation for creation of the ad. Findings confirm the importance of popularity ratings on consumer ad evaluation, and also suggest that certain source effects result in consumers being more critical in their evaluation of the ads