Abstract: In general, the subject matter described in this specification can be embodied in methods, systems, and program products. A score for each of a plurality of authors of posts submitted to a server system is determined. The score for each individual author in the plurality is based on a score of one or more authors in the plurality that have requested to subscribe to a stream of posts that the individual author submits to the server system. A particular post submitted by a particular author in the plurality is received at the server system and from a computing device. A score is assigned to the particular post based on a score of the particular author. The particular post is transmitted from the server system to computing devices that are associated with authors who have requested to subscribe to posts by the particular author.

Abstract: In general, the subject matter described in this specification can be embodied in methods, systems and program products. A server system receives from a plurality of computing devices indications that a user of each of the computing devices requested to receive posts that a first user authors. The server system receives from a first computing device a post that was authored by the first user. The post is transmitted from the server system to the plurality of computing devices. A score for the post is determined to satisfy a criteria for transmission to a second user who has not requested to receive posts authored by the first user. The determination uses a distance of the second user to the first user in a social network graph. In response, the post is transmitted from the server system to a second computing device that is associated with the second user.

Abstract: A payment service is configured to support purchase transactions generated by merchant point-of-sale (POS) devices, wherein each purchase transaction may comprise multiple transaction requests such as authorization requests and capture requests. Each transaction request may be sent to a different one of multiple data centers of the payment service. Upon successfully receiving an acknowledgement from one of the data centers for a transaction request, the POS device designates that data center as the primary data center. Subsequently, all transaction requests for that transaction identify the primary data center, even when the transaction requests are sent to other data centers. At the payment service, the data centers synchronize requests such that the primary data center is informed of all authorizations and is made responsible for performing the capture of the transaction. This allows the primary data center to detect duplicate authorizations and to prevent duplicate captures.

Abstract: A system for managing event streams is provided that includes a volatile memory, a non-volatile memory, and a processor. The volatile memory is configured to store, for each of a plurality of event streams associated with the client device, metadata indicative of events not yet delivered to a client device and the content associated with only a most recent event of the event stream. The non-volatile memory is configured to store the content associated with each of undelivered events. The processor is configured to, upon receiving a request from the client device, retrieve from the volatile memory, without accessing the non-volatile memory, data indicative of a current state of an event stream associated with the client device. The processor is further configured to deliver the retrieved data indicative of the current state of the event stream.

Abstract: In general, the subject matter described in this specification can be embodied in methods, systems and program products. A server system receives from a plurality of computing devices indications that a user of each of the computing devices requested to receive posts that a first user authors. The server system receives from a first computing device a post that was authored by the first user. The post is transmitted from the server system to the plurality of computing devices. A score for the post is determined to satisfy a criteria for transmission to a second user who has not requested to receive posts authored by the first user. The determination uses a distance of the second user to the first user in a social network graph. In response, the post is transmitted from the server system to a second computing device that is associated with the second user.

Abstract: A system for managing event streams is provided that includes a volatile memory, a non-volatile memory, and a processor. The volatile memory is configured to store, for each of a plurality of event streams associated with the client device, metadata indicative of events not yet delivered to a client device and the content associated with only a most recent event of the event stream. The non-volatile memory is configured to store the content associated with each of undelivered events. The processor is configured to, upon receiving a request from the client device, retrieve from the volatile memory, without accessing the non-volatile memory, data indicative of a current state of an event stream associated with the client device. The processor is further configured to deliver the retrieved data indicative of the current state of the event stream.

Abstract: In general, the subject matter described in this specification can be embodied in methods, systems and program products. A server system receives from a plurality of computing devices indications that a user of each of the computing devices requested to receive posts that a first user authors. The server system receives from a first computing device a post that was authored by the first user. The post is transmitted from the server system to the plurality of computing devices. A score for the post is determined to satisfy a criteria for transmission to a second user who has not requested to receive posts authored by the first user. The determination uses a distance of the second user to the first user in a social network graph. In response, the post is transmitted from the server system to a second computing device that is associated with the second user.

Abstract: A system for managing event streams is provided that includes a volatile memory, a non-volatile memory, and a processor. The volatile memory is configured to store, for each of a plurality of event streams associated with the client device, metadata indicative of events not yet delivered to a client device and the content associated with only a most recent event of the event stream. The non-volatile memory is configured to store the content associated with each of undelivered events. The processor is configured to, upon receiving a request from the client device, retrieve from the volatile memory, without accessing the non-volatile memory, data indicative of a current state of an event stream associated with the client device. The processor is further configured to deliver the retrieved data indicative of the current state of the event stream.

Abstract: In general, the subject matter described in this specification can be embodied in methods, systems, and program products. A score for each of a plurality of authors of posts submitted to a server system is determined. The score for each individual author in the plurality is based on a score of one or more authors in the plurality that have requested to subscribe to a stream of posts that the individual author submits to the server system. A particular post submitted by a particular author in the plurality is received at the server system and from a computing device. A score is assigned to the particular post based on a score of the particular author. The particular post is transmitted from the server system to computing devices that are associated with authors who have requested to subscribe to posts by the particular author.

Abstract: A system for managing event streams is provided that includes a volatile memory, a non-volatile memory, and a processor. The volatile memory is configured to store, for each of a plurality of event streams associated with the client device, metadata indicative of events not yet delivered to a client device and the content associated with only a most recent event of the event stream. The non-volatile memory is configured to store the content associated with each of undelivered events. The processor is configured to, upon receiving a request from the client device, retrieve from the volatile memory, without accessing the non-volatile memory, data indicative of a current state of an event stream associated with the client device. The processor is further configured to deliver the retrieved data indicative of the current state of the event stream.

Abstract: A system for managing event streams is provided that includes a volatile memory, a non-volatile memory, and a processor. The volatile memory is configured to store, for each of a plurality of event streams associated with the client device, metadata indicative of events not yet delivered to a client device and the content associated with only a most recent event of the event stream. The non-volatile memory is configured to store the content associated with each of undelivered events. The processor is configured to, upon receiving a request from the client device, retrieve from the volatile memory, without accessing the non-volatile memory, data indicative of a current state of an event stream associated with the client device. The processor is further configured to deliver the retrieved data indicative of the current state of the event stream.

Abstract: A computer-implemented method can include accessing a micro-blog to retrieve a real-time copy of the micro-blog thread and delivering the real-time copy of the micro-blog thread for display in an e-mail message.

Abstract: In general, the subject matter described in this specification can be embodied in methods, systems, and program products. A score for each of a plurality of authors of posts submitted to a server system is determined. The score for each individual author in the plurality is based on a score of one or more authors in the plurality that have requested to subscribe to a stream of posts that the individual author submits to the server system. A particular post submitted by a particular author in the plurality is received at the server system and from a computing device. A score is assigned to the particular post based on a score of the particular author. The particular post is transmitted from the server system to computing devices that are associated with authors who have requested to subscribe to posts by the particular author.

Abstract: A payment service is configured to support purchase transactions generated by merchant point-of-sale (POS) devices, wherein each purchase transaction may comprise multiple transaction requests such as authorization requests and capture requests. Each transaction request may be sent to a different one of multiple data centers of the payment service. Upon successfully receiving an acknowledgement from one of the data centers for a transaction request, the POS device designates that data center as the primary data center. Subsequently, all transaction requests for that transaction identify the primary data center, even when the transaction requests are sent to other data centers. At the payment service, the data centers synchronize requests such that the primary data center is informed of all authorizations and is made responsible for performing the capture of the transaction. This allows the primary data center to detect duplicate authorizations and to prevent duplicate captures.

Abstract: A system for managing event streams is provided that includes a volatile memory, a non-volatile memory, and a processor. The volatile memory is configured to store, for each of a plurality of event streams associated with the client device, metadata indicative of events not yet delivered to a client device and the content associated with only a most recent event of the event stream. The non-volatile memory is configured to store the content associated with each of undelivered events. The processor is configured to, upon receiving a request from the client device, retrieve from the volatile memory, without accessing the non-volatile memory, data indicative of a current state of an event stream associated with the client device. The processor is further configured to deliver the retrieved data indicative of the current state of the event stream.

Abstract: A system for managing event streams is provided that includes a volatile memory, a non-volatile memory, and a processor. The volatile memory is configured to store, for each of a plurality of event streams associated with the client device, metadata indicative of events not yet delivered to a client device and the content associated with only a most recent event of the event stream. The non-volatile memory is configured to store the content associated with each of undelivered events. The processor is configured to, upon receiving a request from the client device, retrieve from the volatile memory, without accessing the non-volatile memory, data indicative of a current state of an event stream associated with the client device. The processor is further configured to deliver the retrieved data indicative of the current state of the event stream.

Abstract: In general, the subject matter described in this specification can be embodied in methods, systems, and program products. A score for each of a plurality of authors of posts submitted to a server system is determined. The score for each individual author in the plurality is based on a score of one or more authors in the plurality that have requested to subscribe to a stream of posts that the individual author submits to the server system. A particular post submitted by a particular author in the plurality is received at the server system and from a computing device. A score is assigned to the particular post based on a score of the particular author. The particular post is transmitted from the server system to computing devices that are associated with authors who have requested to subscribe to posts by the particular author.

Abstract: In general, the subject matter described in this specification can be embodied in methods, systems and program products. A server system receives from a plurality of computing devices indications that a user of each of the computing devices requested to receive posts that a first user authors. The server system receives from a first computing device a post that was authored by the first user. The post is transmitted from the server system to the plurality of computing devices. A score for the post is determined to satisfy a criteria for transmission to a second user who has not requested to receive posts authored by the first user. The determination uses a distance of the second user to the first user in a social network graph. In response, the post is transmitted from the server system to a second computing device that is associated with the second user.

Abstract: In general, the subject matter described in this specification can be embodied in methods, systems and program products. A server system receives from a plurality of computing devices indications that a user of each of the computing devices requested to receive posts that a first user authors. The server system receives from a first computing device a post that was authored by the first user. The post is transmitted from the server system to the plurality of computing devices. A score for the post is determined to satisfy a criteria for transmission to a second user who has not requested to receive posts authored by the first user. The determination uses a distance of the second user to the first user in a social network graph. In response, the post is transmitted from the server system to a second computing device that is associated with the second user.

Abstract: A computer-implemented method can include accessing a micro-blog to retrieve a real-time copy of the micro-blog thread and delivering the real-time copy of the micro-blog thread for display in an e-mail message.