Content selection using performance metrics

1. A method comprising:

receiving publisher selections of advertisements from a plurality of advertisements;

associating the selected advertisements with an advertisement environment in a document, wherein the advertisement environment is associated with a location in the document for presenting one or more advertisements;

generating, by one or more processors, an advertisement request code for inclusion in the document, the advertisement request code configured to issue an advertisement request for selection of an advertisement from the selected advertisements for presentation in the advertisement environment;

evaluating performance metrics for the selected advertisements presented in the advertisement environment;

determining that the selected advertisements do not meet a performance threshold;

in response to determining that the selected advertisements do not meet the performance threshold, optimizing the selection of selected advertisements based on the performance metrics comprising overriding the publisher selections;

substituting a selected advertisement with a candidate advertisement of a plurality of candidate advertisements, wherein the candidate advertisements are different than the selected advertisements; and

providing the candidate advertisement instead of the selected advertisement to a client device for rendering in the advertisement environment of the document.

2. The method of claim 1 , wherein the performance metrics include a click-through rate or a conversion rate.

3. The method of claim 1 , further comprising:

estimating performance metrics for a plurality of candidate advertisements; and

identifying a candidate advertisement from the plurality of candidate advertisements with performance metrics greater than a performance threshold.

4. The method of claim 3 , comprising:

identifying a plurality of candidate advertisements based on a context of the document or advertisements related to the selected advertisements.

5. A computer program product stored on a computer storage device comprising instructions that when executed by one or more processors cause the processors to perform operations comprising:

receiving publisher selections of advertisements from a plurality of advertisements;

associating the selected advertisements with an advertisement environment in a document, wherein the advertisement environment is associated with a location in the document for presenting one or more advertisements;

generating, by one or more processors, an advertisement request code for inclusion in the document, the advertisement request code configured to issue an advertisement request for selection of an advertisement from the selected advertisements for presentation in the advertisement environment;

evaluating performance metrics for the selected advertisements presented in the advertisement environment;

determining that the selected advertisements do not meet a performance threshold;

in response to determining that the selected advertisements do not meet the performance threshold, optimizing the selection of selected advertisements based on the performance metrics comprising overriding the publisher selections;

substituting a selected advertisement with a candidate advertisement of a plurality of candidate advertisements, wherein the candidate advertisements are different than the selected advertisements; and

providing the candidate advertisement instead of the selected advertisement to a client device for rendering in the advertisement environment of the document.

6. The computer program product of claim 5 , wherein the performance metrics include a click-through rate, or a conversion rate.

7. The computer program product of claim 5 , wherein the operations further comprise:

estimating performance metrics for a plurality of candidate advertisements; and

identifying a candidate advertisement from the plurality of candidate advertisements with performance metrics greater than a performance threshold.

8. The computer program product of claim 7 , wherein the instructions comprise:

identifying a plurality of candidate advertisements based on a context of the document or advertisements related to the selected advertisements.

9. A system comprising:

one or more computers and one or more storage devices storing instructions that are operable, when executed by the one or more computers, to cause the one or more computers to perform operations comprising:

receiving publisher selections of advertisements from a plurality of advertisements;

associating the selected advertisements with an advertisement environment in a document, wherein the advertisement environment is associated with a location in the document for presenting one or more advertisements;

generating, by one or more processors, an advertisement request code for inclusion in the document, the advertisement request code configured to issue an advertisement request for selection of an advertisement from the selected advertisements for presentation in the advertisement environment;

evaluating performance metrics for the selected advertisements presented in the advertisement environment;

determining that the selected advertisements do not meet a performance threshold;

in response to determining that the selected advertisements do not meet the performance threshold, optimizing the selection of selected advertisements based on the performance metrics comprising overriding the publisher selections;

substituting a selected advertisement with a candidate advertisement of a plurality of candidate advertisements, wherein the candidate advertisements are different than the selected advertisements; and

providing the candidate advertisement instead of the selected advertisement to a client device for rendering in the advertisement environment of the document.

10. The system of claim 9 , wherein the performance metrics include a click-through rate, or a conversion rate.

11. The system of claim 9 , wherein the operations further comprise:

estimating performance metrics for a plurality of candidate advertisements; and

identifying a candidate advertisement from the plurality of candidate advertisements with performance metrics greater than a performance threshold.

12. The system of claim 11 , wherein the instructions comprise:

identifying a plurality of candidate advertisements based on a context of the document or advertisements related to the selected advertisements.