Providing content in response to user actions

A non-transitory computer storage medium encoded with a computer program, the computer program comprising instructions that when executed by one or more data processing apparatus cause the one or more data processing apparatus to perform operations comprising:

• identifying, within a database structure, a list of users that performed a particular action at an online resource of a first entity;
• receiving a search query that does not reference the first entity from a client device of a particular user that is accessing one or more online resources of an entity that differs from the first entity;
• and
• responding to the search query received form the client device of the particular user, including:
• determining that the search query matches a distribution parameter for a set of content items;
• determining, based on information contained in a cookie at the client device, whether the particular user that submitted the search query is included in the list of users that performed the particular action at the online resource of the first entity independent of the first entity being a follower of the particular user in a social network and independent of whether social network friends of the particular user performed the particular action at the online resource of the first entity;
• when the particular user that submitted the search query is determined to be included in the list of users that performed the particular action at the online resource of the first entity, selecting, from among the set of content items having the distribution parameter, a first content item provided by the first entity having distribution parameters specifying that the first content item is to be provided to users that (i) are included in the list of users that performed the particular action at the online resource of the first entity and that (ii) submit the search query that matches the distribution parameter;
• otherwise, selecting, by the one or more data processing apparatus, a different content item that is provided by a different entity;
• and
• providing, by the one or more data processing apparatus, one of the first content item or the different content item that was selected.

A system comprising:

• a first data store storing entity definitions for a plurality of entities;
• a second data store storing information for users who performed actions at online resources associated with the plurality of entities;
• a third data store storing distribution parameters for eligible content items, the distribution parameters identified by at least content sponsors and specifying conditions for selecting content items from among the eligible content items for presentation to users that that performed particular actions at online resources of the plurality of entities;
• and
• one or more data processing apparatus configured to interact with the first, second, and third data stores, the one or more data processing apparatus being further configured to perform operations comprising:
• identifying a list of users that performed a particular action at an online resource of a first entity;
• receiving a search query that does not reference the first entity from a client device of a particular user that is accessing one or more online resources of an entity that differs from the first entity;
• and
• responding to the search query received form the client device of the particular user, including:
• determining that the search query matches a distribution parameter for a set of content items;
• determining, based on information contained in a cookie at the client device, whether the particular user that submitted the search query is included in the list of users that performed the particular action at the online resource of the first entity independent of the first entity being a follower of the particular user in a social network and independent of whether social network friends of the particular user performed the particular action at the online resource of the first entity;
• when the particular user that submitted the search query is determined to be included in the list of users that performed the particular action at the online resource of the first entity, selecting, from among the set of content items having the distribution parameter, a first content item provided by the first entity having distribution parameters specifying that the content item is to be provided to users that (i) are included in the list of users that performed the particular action at the online resource of the first entity and that (ii) submit the search query that matches the distribution parameter;
• otherwise selecting a different content item that is provided by a different entity;
• and
• providing one of the first content item or the different content item that was selected.