An online system extracts features from an application linked to the online system. The application is used by users of the online system and posts content to the online system. A trained model is applied to the extracted features to generate a quality score for the application. The trained model is trained using features extracted from a set of training applications and quality scores manually assigned to the training applications, wherein the manually assigned quality scores indicate whether each training application satisfies a set of criteria and the generated quality score represents a probability of the application satisfying the set of criteria. Based on the quality score, content provided by the application is ranked for presentation to a user of the online system in relation to other content of the online system. The online system presents the content provided by the application to the user according to the ranking
Please help me write a proper abstract based on the patent claims. CLAIM: 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. 2. The method of claim 1, wherein ranking the content provided by the application in relation to other content of the online system comprises: generating a quality score for each of a plurality of other applications linked to the online system; and ranking the content provided by the application in relation to content provided by the plurality of other applications based on the quality score of the application and the quality scores of each of the plurality of other applications. 3. The method of claim 1, wherein presenting the content provided by the application comprises: presenting the content to the user as one or more stories in a newsfeed. 4. The method of claim 3, wherein presenting the content as one or more stories in the newsfeed comprises: responsive to the quality score being below a threshold, presenting the one or more stories at a lower position in the newsfeed than stories associated with the other content of the online system. 5. The method of claim 3, wherein presenting the content as one or more stories in the newsfeed comprises: responsive to the quality score being below a threshold, presenting the one or more stories less frequently in the newsfeed than stories associated with the other content of the online system. 6. The method of claim 1, wherein the extracted features comprise one or more of user feedback on the application, usage of the application, business value of the application, and configuration of the application. 7. The method of claim 1, wherein the generated quality score represents a quality of the application and a quality of the content posted by the application to the online system. 8. The method of claim 1, wherein the manually assigned quality scores are binary scores assigned to the applications in the training set, and wherein a high quality score is assigned to a training application satisfying the set of criteria and a low quality score is assigned to a training application not satisfying one or more of the criteria. 9. A computer program product comprising a non-transitory computer-readable storage medium containing computer program code for: 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. 10. The computer program product of claim 9, wherein ranking the content provided by the application in relation to other content of the online system comprises: generating a quality score for each of a plurality of other applications linked to the online system; and ranking the content provided by the application in relation to content provided by the plurality of other applications based on the quality score of the application and the quality scores of each of the plurality of other applications. 11. The computer program product of claim 9, wherein presenting the content provided by the application comprises: presenting the content to the user as one or more stories in a newsfeed. 12. The computer program product of claim 11, wherein presenting the content as one or more stories in the newsfeed comprises: responsive to the quality score being below a threshold, presenting the one or more stories at a lower position in the newsfeed than stories associated with the other content of the online system. 13. The computer program product of claim 11, wherein presenting the content as one or more stories in the newsfeed comprises: responsive to the quality score being below a threshold, presenting the one or more stories less frequently in the newsfeed than stories associated with the other content of the online system. 14. The computer program product of claim 9, wherein the extracted features comprise one or more of user feedback on the application, usage of the application, business value of the application, and configuration of the application. 15. The computer program product of claim 9, wherein the generated quality score represents a quality of the application and a quality of the content posted by the application to the online system. 16. The computer program product of claim 9, wherein the manually assigned quality scores are binary scores assigned to the applications in the training set, and wherein a high quality score is assigned to a training application satisfying the set of criteria and a low quality score is assigned to a training application not satisfying one or more of the criteria.