An online system classifies users based on their propensity to adopt one or more innovations in a subject area. To classify the users, the online system maintains information associated with one or more actions performed by the user and content provided by the user, with actions and the content associated with adopting one or more innovations in the subject area. The online system determines a score for a pairing of the user and the subject area based on the maintained one or more actions and/or the content associated with adopting the one or more innovations in the subject area. Based on the determined score, the online system determines an innovation adoption label for the user that represents a propensity of the user to adopt one or more innovations in the subject area.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A computer-implemented method comprising: maintaining, at an online system, information associated with a user, the information describing one or more actions associated with adopting one or more innovations in a subject area performed by the user and content associated with the one or more innovations in the subject area provided by the user to the online system; retrieving the one or more actions associated with adopting the one or more innovations in the subject area from the maintained information, each action associated with a time when the user performed the action; retrieving the content associated with the one or more innovations in the subject area provided by the user to the online system from the maintained information; determining a score associated with a pairing of the user and the subject area based at least in part on the times associated with the retrieved one or more actions and one or more characteristics of the retrieved content associated with the one or more innovations in the subject area; and generating an innovation adoption label associated with the user and the subject area based at least in part on the score, the innovation adoption label representing a propensity of the user for adopting one or more innovations in the subject area. 2. The computer-implemented method of claim 1, wherein the one or more characteristics of the retrieved content comprises a time when the user provided the content to the online system. 3. The computer-implemented method of claim 1, wherein determining the score associated with the pairing of the user and the subject area comprises: determining differences between times associated with retrieved one or more actions and times when the retrieved one or more actions were initially capable of being performed; and determining the score based at least in part on the determined differences. 4. The computer-implemented method of claim 1, wherein determining the score associated with the pairing of the user and the subject area comprises: determining a number of messages received by the user associated with an innovation in the subject area received by the user at times prior to a time associated with an action associated with adopting the innovation in the subject area performed by the user from the retrieved one or more actions; and; determining the score based at least in part on the determined number of messages. 5. The computer-implemented method of claim 4, wherein determining the number of messages received by the user associated with the innovation in the subject area received by the user at times prior to the time associated with the action associated with adopting the innovation in the subject area performed by the user from the retrieved one or more actions comprises: determining a number of messages received by the user associated with an innovation in the subject area received from additional users by the user at times prior to a time associated with an action associated with adopting the innovation in the subject area performed by the user from the retrieved one or more actions. 6. The computer-implemented method of claim 4, wherein determining the number of messages received by the user associated with the innovation in the subject area received by the user at times prior to the time associated with the action associated with adopting the innovation in the subject area performed by the user from the retrieved one or more actions comprises: determining a number of messages received by the user associated with an innovation in the subject area received from the online system by the user at times prior to a time associated with an action associated with adopting the innovation in the subject area performed by the user from the retrieved one or more actions. 7. The computer-implemented method of claim 1, wherein determining the score associated with the pairing of the user and the subject area comprises: determining a number of messages associated with an innovation in the subject area sent by the user to additional users of the online system; and; determining the score based at least in part on the determined number of messages. 8. The computer-implemented method of claim 1, wherein determining the score associated with the pairing of the user and the subject area comprises: determining a rating of an innovation in the subject area based at least in part on retrieved content associated with the one or more innovations in the subject area; determining an average rating of the innovation in the subject area based on content provided to the online system from additional users; and determining the score based at least in part on a difference between the determined rating and the determined average rating. 9. The computer-implemented method of claim 1, wherein determining the score associated with the pairing of the user and the subject area comprises: determining an influencer score associated with the user, the influencer score providing a measure of the influence of the user on actions performed by additional users connected to the user via the online system; and determining the score based at least in part on the influencer score associated with the user. 10. The computer-implemented method of claim 9, wherein determining the score based at least in part on the influencer score associated with the user comprises: increasing the score in response to determining the influencer score associated with the user is greater than a threshold value; and decreasing the score in response to determining the influencer score associated with the user is less than the threshold value. 11. The computer-implemented method of claim 1, wherein generating the innovation adoption label associated with the user and the subject area based at least in part on the score comprises: maintaining a plurality of innovation adoption labels, each innovation adoption label corresponding to a range of scores for the pairing of the user and the subject area; and associating an innovation adoption label corresponding to a range of scores including the score with the user. 12. A computer program product comprising a computer readable storage medium having instructions encoded thereon that, when executed by a processor, cause the processor to: maintain, at an online system, information associated with a user, the information describing one or more actions associated with adopting one or more innovations in a subject area performed by the user and content associated with the one or more innovations in the subject area provided by the user to the online system; retrieve the one or more actions associated with adopting the one or more innovations in the subject area from the maintained information, each action associated with a time when the user performed the action; retrieve the content associated with the one or more innovations in the subject area provided by the user to the online system from the maintained information; determine a score associated with a pairing of the user and the subject area based at least in part on the times associated with the retrieved one or more actions and one or more characteristics of the retrieved content associated with the one or more innovations in the subject area; and generate an innovation adoption label associated with the user and the subject area based at least in part on the score, the innovation adoption label representing a propensity of the user for adopting one or more innovations in the subject area. 13. The computer program product of claim 12, wherein the one or more characteristics of the retrieved content comprises a time when the user provided the content to the online system. 14. The computer program product of claim 12, wherein determine the score associated with the pairing of the user and the subject area comprises: determine differences between times associated with retrieved one or more actions and times when the retrieved one or more actions were initially capable of being performed; and determine the score based at least in part on the determined differences. 15. The computer program product of claim 12, wherein determine the score associated with the pairing of the user and the subject area comprises: determine a number of messages received by the user associated with an innovation in the subject area received by the user at times prior to a time associated with an action associated with adopting the innovation in the subject area performed by the user from the retrieved one or more actions; and; determine the score based at least in part on the determined number of messages. 16. The computer program product of claim 15, wherein determine the number of messages received by the user associated with the innovation in the subject area received by the user at times prior to the time associated with the action associated with adopting the innovation in the subject area performed by the user from the retrieved one or more actions comprises: determine a number of messages received by the user associated with an innovation in the subject area received from additional users by the user at times prior to a time associated with an action associated with adopting the innovation in the subject area performed by the user from the retrieved one or more actions. 17. The computer program product of claim 15, wherein determine the number of messages received by the user associated with the innovation in the subject area received by the user at times prior to the time associated with the action associated with adopting the innovation in the subject area performed by the user from the retrieved one or more actions comprises: determine a number of messages received by the user associated with an innovation in the subject area received from the online system by the user at times prior to a time associated with an action associated with adopting the innovation in the subject area performed by the user from the retrieved one or more actions. 18. The computer program product of claim 12, wherein determine the score associated with the pairing of the user and the subject area comprises: determine a number of messages associated with an innovation in the subject area sent by the user to additional users of the online system; and; determine the score based at least in part on the determined number of messages. 19. The computer program product of claim 12, wherein determine the score associated with the pairing of the user and the subject area comprises: determine a rating of an innovation in the subject area based at least in part on retrieved content associated with the one or more innovations in the subject area; determine an average rating of the innovation in the subject area based on content provided to the online system from additional users; and determine the score based at least in part on a difference between the determined rating and the determined average rating. 20. The computer program product of claim 12, wherein generating the innovation adoption label associated with the user and the subject area based at least in part on the score comprises: maintain a plurality of innovation adoption labels, each innovation adoption label corresponding to a range of scores for the pairing of the user and the subject area; and associate an innovation adoption label corresponding to a range of scores including the score with the user.