In one embodiment, a method includes accessing identifying information for one or more endpoints of a user. Each of the endpoints corresponds to a particular communication medium. The method also includes calculating a confidence score associated with one or more of the endpoints of the user. The confidence score is calculated based one or more signals associated with the respective endpoint. The method also includes comparing the calculated confidence score to a pre-determined threshold score; and determining the identifying information is currently valid based on the calculated confidence score satisfying the pre-determined threshold score.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. A method comprising: by a computing device, accessing identifying information for one or more endpoints of a user, wherein each of the endpoints corresponds to a particular communication medium; by the computing device, calculating a confidence score associated with one or more of the endpoints of the user, wherein the confidence score is calculated based one or more signals associated with the respective endpoint; by the computing device, comparing the calculated confidence score to a pre-determined threshold score; and by the computing device, determining the identifying information is currently valid based on the calculated confidence score satisfying the pre-determined threshold score. 2. The method of claim 1, wherein the identifying information comprises a telephone number, e-mail address, unique device identifier, user-account identifier for a particular application, or user-account identifier for a client device of the user. 3. The method of claim 1, wherein the communication medium comprises short-messaging service (SMS) messaging, multi-media messaging service (MMS) messaging, e-mail, an application interface, or telephonic communication. 4. The method of claim 1, further comprising prompting the user to provide updated identifying information in response to the calculated confidence score being lower than the pre-determined threshold score. 5. The method of claim 1, further comprising sending, to the user, one or more messages satisfying the pre-determined threshold score. 6. The method of claim 1, wherein the signals comprise positive signals and negative signals, wherein the negative signals correspond to a signal associated with a change in the identifying information, and wherein the positive signals correspond to a signal associated with valid identifying information. 7. The method of claim 6, wherein the calculating comprises applying the signals to a predictor function, wherein the predictor function comprises a weighted function of the positive signals and negative signals, the weighted function comprising one or more weights to the signals. 8. The method of claim 7, wherein at least one of the one or more weights have a time-dependency. 9. The method of claim 7, wherein values of one or more the weights are determined by applying a machine-learning algorithm to a set of training data to optimize the values of the weights so that the predictor function matches a known result associated with the set of training data. 10. The method of claim 9, wherein the set of training data is obtained from one or more users that are prompted to confirm their identifying information. 11. The method of claim 6, wherein the positive and negative signals each comprise strong and weak signals, wherein the weak signals modify the calculated confidence score by an incremental amount, and wherein the strong signals modify the calculated confident score by a relatively large amount relative to the weak signals. 12. The method of claim 6, wherein: the negative signals comprise: (1) a signal indicating that the identifying information for the endpoint is invalid, (2) a signal indicating that the user confirmed different information for one or more of the endpoints, (3) a signal confirming use of one or more of the endpoints by a different user, or (4) a signal confirming different identifying information for one or more of the endpoints based on contact information from another user; and the positive signals comprise: (1) a signal indicating that the identifying information for the endpoint is valid, (2) a signal indicating that the user confirmed the identifying information for one or more of the endpoints, (3) a signal indicating that activity log information confirms the identifying information for one or more of the endpoints, or (4) a signal confirming the identifying information for one or more of the endpoints based on contact information from another user. 13. The method of claim 1, wherein the calculated confidence score corresponds to a probability that the identifying information is valid for a respective endpoint. 14. One or more computer-readable non-transitory storage media embodying software configured when executed to: access identifying information for one or more endpoints of a user, wherein each of the endpoints corresponds to a particular communication medium; calculate a confidence score associated with one or more of the endpoints of the user, wherein the confidence score is calculated based one or more signals associated with the respective endpoint; compare the calculated confidence score to a pre-determined threshold score; and determine the identifying information is currently valid based on the calculated confidence score satisfying the pre-determined threshold score. 15. The media of claim 14, wherein the identifying information comprises a telephone number, an e-mail address, a unique device identifier, a user account identifier for a particular application, or a user-account identifier for a client device of the user. 16. The media of claim 14, wherein the communication medium comprises short-messaging service (SMS) messaging, multi-media messaging service (MMS) messaging, e-mail, an application interface, or telephonic communication. 17. The media of claim 14, wherein the software is further configured to prompt the user to provide updated identifying information in response to the calculated confidence score being lower than the pre-determined threshold score. 18. A device comprising: one or more processors; and one or more computer-readable non-transitory storage media coupled to the processors and embodying software configured when executed to: access identifying information for one or more endpoints of a user, wherein each of the endpoints corresponds to a particular communication medium; calculate a confidence score associated with one or more of the endpoints of the user, wherein the confidence score is calculated based one or more signals associated with the respective endpoint; compare the calculated confidence score to a pre-determined threshold score; and determine the identifying information is currently valid based on the calculated confidence score satisfying the pre-determined threshold score. 19. The device of claim 18, wherein the identifying information comprises a telephone number, an e-mail address, a unique device identifier, a user account identifier for a particular application, or a user-account identifier for a client device of the user. 20. The device of claim 18, wherein the communication medium comprises short-messaging service (SMS) messaging, multi-media messaging service (MMS) messaging, e-mail, an application interface, or telephonic communication.