Abstract: Access to some aspect of a service may be limited until a user has invested in performing some amount of computation. Legitimate users typically have excess cycles on their machines, which can be used to perform computation at little or no cost to the user. By contrast, computation is expensive for for-profit internet abusers (e.g., spammers). These abusers typically use all of their computing resources to run “bots” that carry out their schemes, so computation increases the abuser's cost by forcing him or her to acquire new computing resources or to rent computer time. Thus, the providers of free services (e.g., web mail services, blogging sites, etc.), can allow newly registered users to use some limited form of the service upon registration. However, in order to make more extensive use of the service, the user can be asked to prove his legitimacy by investing in some amount of computation.

Abstract: A Web browser of a computing device downloads or otherwise obtains a file. File information identifying the file is obtained and is sent to a remote reputation service. Client information identifying aspects of the computing device can also optionally be sent to the remote reputation service. In response to the file information (and optionally client information), a reputation indication for the file is received from the remote reputation service. A user interface for the Web browser to present at the computing device is determined, based at least in part on the reputation indication, and presented at the computing device.

Abstract: A reputation based redirection service is usable to build URL wrappers for un-trusted and unknown URLs. Such URL wrappers can be used to protect Web users by, for example, redirecting traffic to interstitial Web pages. Additionally, reputation decisions can be made by the service to further protect users from malicious URLs.

Abstract: Online risk mitigation techniques are described. In an implementation, a service is queried for a reputation associated with an object from an online source in response to selection of the object. A backup of a client that is to receive the object is stored prior to obtaining the object when the reputation does not meet a threshold reputation level.

Abstract: A Web browser of a computing device downloads or otherwise obtains a file. File information identifying the file is obtained and is sent to a remote reputation service. Client information identifying aspects of the computing device can also optionally be sent to the remote reputation service. In response to the file information (and optionally client information), a reputation indication for the file is received from the remote reputation service. A user interface for the Web browser to present at the computing device is determined, based at least in part on the reputation indication, and presented at the computing device.

Abstract: Access to some aspect of a service may be limited until a user has invested in performing some amount of computation. Legitimate users typically have excess cycles on their machines, which can be used to perform computation at little or no cost to the user. By contrast, computation is expensive for for-profit internet abusers (e.g., spammers). These abusers typically use all of their computing resources to run “bots” that carry out their schemes, so computation increases the abuser's cost by forcing him or her to acquire new computing resources or to rent computer time. Thus, the providers of free services (e.g., web mail services, blogging sites, etc.), can allow newly registered users to use some limited form of the service upon registration. However, in order to make more extensive use of the service, the user can be asked to prove his legitimacy by investing in some amount of computation.

Abstract: A reputation based redirection service is usable to build URL wrappers for un-trusted and unknown URLs. Such URL wrappers can be used to protect Web users by, for example, redirecting traffic to interstitial Web pages. Additionally, reputation decisions can be made by the service to further protect users from malicious URLs.

Abstract: Functionality is described for addressing a threat to the security of a user device that utilizes a network-accessible service. The functionality operates by assessing the likelihood that the user device is infected by the undesirable item. When the user device makes a request to access the network-accessible service, the functionality can interact with the user device in a manner that is governed by the assessed likelihood that the user device is infected by the undesirable item.

Abstract: Online risk mitigation techniques are described. In an implementation, a service is queried for a reputation associated with an object from an online source in response to selection of the object. A backup of a client that is to receive the object is stored prior to obtaining the object when the reputation does not meet a threshold reputation level.

Abstract: Functionality is described for addressing a threat to the security of a user device that utilizes a network-accessible service. The functionality operates by assessing the likelihood that the user device is infected by the undesirable item. When the user device makes a request to access the network-accessible service, the functionality can interact with the user device in a manner that is governed by the assessed likelihood that the user device is infected by the undesirable item.

Abstract: A data transmission system transmits data from a first device to an interface device at a continuous rate and includes a first device for storing data and for transmitting data at a first data output rate. An interface device outputs data at a second data output rate different from the first data output rate. A preload buffer initially receives a predetermined amount of data from the first device and stores the initially received data. The preload buffer also transmits at least a portion of the initially received data at a third data output rate. The preload buffer receives additional data from the first device as the initially received data is transmitted from the preload buffer. A first buffer and a second buffer of generally equal size are sized to receive a single block of data from the preload buffer. The size of the single block of data is less than the predetermined amount of output data initially received and stored in the preload buffer.