Many small organizations lack the expertise and resources to conduct usability evaluations of their websites. Social Overlays, presented here, is a new system that allows a community of users to collectively improve their website.Social Overlays enables end–users to identify and repair common user interface problems through creating “overlays” on web pages as part of their regular use, thereby improving usability while reducing the need for professional services. In short, Social Overlays harnesses the diversity of experience and ideas within a community to "crowd source" usability.To evaluate Social Overlays, we examined whether a group of community members without any usability training could use Social Overlays to identify and repair UI problems on their medium–sized community’s website. We found that they could. Community users were able to uncover a large number of UI problems and formulate reasonable solutions to the problems they identified. In addition, we compared Social Overlays to two standard ways of assessing website usability: expert inspection and usability testing. We found that Social Overlays users identified more problems, and their reported problems differed in useful ways from those found by the experts and the usability testing team.