Abstract: Methods, systems, and apparatus, including computer program products for monitoring an experiment relating to the conversion rates of landing page variants to test landing page designs. One method includes computing respective conversion rates for each of a plurality of corresponding landing page variants, based on the number of times a conversion page is reached from the corresponding landing page variant, and based on the number of times the corresponding landing page variant is reached from one or more advertisements; and computing a confidence interval for each conversion rate. A user monitoring the experiment can be notified if winning or losing variants emerge. A time to completion of the experiment can be estimated. Presentation to browsing users of winning variants can be favored, and losing variants can be disfavored, during the experiment as they emerge.

Abstract: Methods, systems, and apparatus, including computer program products for defining landing pages to test different landing page designs. User input specifies a landing page having sections, each section having an original version of content. User input also specifies one or more additional versions of content, the original and the additional versions together constituting alternative versions, and the landing page with the alternative versions together constituting an experiment. Page fragments are determined. The fragments are added to the landing page and are operable, when interpreted by a client-side browser, to choose one of the alternative versions of each identified section and make each chosen alternative version the content of the corresponding section before the landing page is displayed by the browser. A designer can insert the page fragments into the landing page to produce an instrumented landing page.

Abstract: Methods, systems, and apparatus, including computer program products for showing different landing page designs to a user. One method includes displaying an advertisement on a starting page to a user interacting with a client, the advertisement having a hyperlink to an instrumented landing page; in response to the user selecting the advertisement, downloading the instrumented landing page to the client, the instrumented landing page having one or more sections, each section having a corresponding plurality of alternative versions; choosing in the client a combination of one alternative version for each of the one or more sections; generating in the client a landing page variant, each section of the landing page variant being the corresponding alternative version of the section defined by the combination; notifying a server that the instrumented landing page was reached; notifying the server which combination was chosen; and displaying the landing page variant to the user.

Abstract: Methods, systems, and apparatus, including computer program products for showing different landing page designs to a user. One method includes displaying an advertisement on a starting page to a user interacting with a client, the advertisement having a hyperlink to an instrumented landing page; in response to the user selecting the advertisement, downloading the instrumented landing page to the client, the instrumented landing page having one or more sections, each section having a corresponding plurality of alternative versions; choosing in the client a combination of one alternative version for each of the one or more sections; generating in the client a landing page variant, each section of the landing page variant being the corresponding alternative version of the section defined by the combination; notifying a server that the instrumented landing page was reached; notifying the server which combination was chosen; and displaying the landing page variant to the user.

Abstract: Methods, systems, and apparatus, including computer program products for defining landing pages to test different landing page designs. User input specifies a landing page having sections, each section having an original version of content. User input also specifies one or more additional versions of content, the original and the additional versions together constituting alternative versions, and the landing page with the alternative versions together constituting an experiment. Page fragments are determined. The fragments are added to the landing page and are operable, when interpreted by a client-side browser, to choose one of the alternative versions of each identified section and make each chosen alternative version the content of the corresponding section before the landing page is displayed by the browser. A designer can insert the page fragments into the landing page to produce an instrumented landing page.

Abstract: Methods, systems, and apparatus, including computer program products for monitoring an experiment relating to the conversion rates of landing page variants to test landing page designs. One method includes computing respective conversion rates for each of a plurality of corresponding landing page variants, based on the number of times a conversion page is reached from the corresponding landing page variant, and based on the number of times the corresponding landing page variant is reached from one or more advertisements; and computing a confidence interval for each conversion rate. A user monitoring the experiment can be notified if winning or losing variants emerge. A time to completion of the experiment can be estimated. Presentation to browsing users of winning variants can be favored, and losing variants can be disfavored, during the experiment as they emerge.

Abstract: Attributes of new account information and advertising campaigns for advertisers are evaluated by a fraud detection engine of a fraud system and a fraud score is augmented where fraud is suspected. The fraud detection engine evaluates the attributes of the advertising campaign, including attributes such as bid amount, maximum cost per day, average bid, and keyword selection.