Abstract: An advertiser specifies a conversion-based bid for a conversion event associated with an ad. If a conversion event occurs for the ad, an effective conversion-based bid can be adjusted by a risk premium associated with the ad. An account associated with the advertiser can be debited based upon the adjusted effective conversion-based bid.

Abstract: An advertiser specifies a conversion-based bid for a conversion event associated with an ad. If a conversion event occurs for the ad, an effective conversion-based bid can be adjusted by a risk premium associated with the ad. An account associated with the advertiser can be debited based upon the adjusted effective conversion-based bid.

Abstract: A system and method for generating a model based on the user's interests and activities by receiving with a logging unit user activities from heterogeneous data sources, generating a log of user activities for a content item by joining the user activities for the content item, expanding attributes of the log by at least one of content and by the user to form an expanded log and generating a user model based on the expanded log. A feature extractor extracts features from content items and assigns weights to the features. A scoring engine receives the model and the content items with their associated weighted features and scores the content items based on the user model. The scoring engine generates a stream of content based on the scored content items.

Abstract: Methods, systems, and apparatus, including computer program products, for determining a probability that a traffic conversion of a content item associated with a content source (e.g., website) will occur based on past traffic patterns for that content source. A traffic conversion defines, for example, minimum traffic interactions of one or more associated user sessions with a content source. The minimum traffic interactions can be based on, for example, the duration of the one or more user sessions on the content source, or a quantity of pages associated with the content source navigated in the one or more associated user sessions.

Abstract: A predicted performance metric of a candidate advertisement in an advertising slot can be received and compared to a baseline predicted performance metric for the candidate advertisement. A target bid associated with the candidate advertisement can be adjusted based upon the comparison, and the adjusted bid can be submitted to an auction for the advertising slot.

Abstract: An advertiser specifies a conversion-based bid for a conversion event associated with an ad. If a conversion event occurs for the ad, an effective conversion-based bid can be adjusted by a risk premium associated with the ad. An account associated with the advertiser can be debited based upon the adjusted effective conversion-based bid.

Abstract: Methods, systems, and apparatus, including computer program products, for determining a probability that a traffic conversion of a content item associated with a content source (e.g., website) will occur based on past traffic patterns for that content source. A traffic conversion defines, for example, minimum traffic interactions of one or more associated user sessions with a content source. The minimum traffic interactions can be based on, for example, the duration of the one or more user sessions on the content source, or a quantity of pages associated with the content source navigated in the one or more associated user sessions.

Abstract: A predicted performance metric of a candidate advertisement in an advertising slot can be received and compared to a baseline predicted performance metric for the candidate advertisement. A target bid associated with the candidate advertisement can be adjusted based upon the comparison, and the adjusted bid can be submitted to an auction for the advertising slot.