1. A method comprising: extracting, by a social networking system, features from an application of a plurality of applications linked to the social networking system, the plurality of applications operate independently of and external to the social networking system, are used by users of the social networking system, are configured to post content to the social networking system on behalf of the users of the social networking system, and each correspond to software that can be installed on a client device of a user of the social networking system that uses data from the social networking system to provide at least one of a service or functionality to the user; identifying, by the social networking system, a set of features from a set of training applications from the plurality of applications, a quality score is manually assigned to each application of the set of training applications and indicating whether each training application satisfies one or more of a set of criteria; comparing, by the social networking system, the features extracted from the application to the identified set of features from the set of training applications; and generating, by the social networking system, an application quality score for the application based on a degree of similarity of the features extracted from the application to the identified set of features from the set of training applications and the quality scores assigned to the set of training applications, the generated application quality score representing a probability of the application satisfying the set of criteria.