1. A method comprising: extracting features from an application linked to an online system, the application used by users of the online system and posting content to the online system; applying a trained model to the extracted features to generate a quality score for the application, wherein the trained model is trained using features extracted from a set of training applications and quality scores manually assigned to the training applications, the manually assigned quality scores indicating whether each training application satisfies a set of criteria and the generated quality score representing a probability of the application satisfying the set of criteria; ranking for presentation to a user of the online system, content provided by the application in relation to other content of the online system based on the generated quality score; and presenting the content provided by the application to the user of the online system according to the ranking.