18. One or more computer storage memory having computer-executable instructions stored thereon, which when executed by one or more processors, causes the one or more processors to perform operations comprising: maintaining a set of models including models authored by crowd contributors, each model comprising one or more of the following: rules, constraints, and equations used by that model to generate one or more searches to obtain a set of content objects associated with that model; receiving a selected model from a user; generating a plan from the selected model, the plan comprising plan objects selected from the set of content objects obtained by the selected model according to one or more of the following: the rules, the constraints, and the equations of the selected model; producing an interactive presentation from the plan for presenting to the first user; receiving, from the user, a change directed towards one or more of the plan objects during the interactive presentation; determining a number of times the change has been made by other users; upon determining that the number of times the change has been made by other users exceeds a threshold, generating a new model based at least in part upon the changed received during the interactive presentation; and upon determining that the number of times the change has been made by other users does not exceed a threshold, revising the plan to include the change without generating a new model based on the changed.
18. One or more computer storage memory having computer-executable instructions stored thereon, which when executed by one or more processors, causes the one or more processors to perform operations comprising: maintaining a set of models including models authored by crowd contributors, each model comprising one or more of the following: rules, constraints, and equations used by that model to generate one or more searches to obtain a set of content objects associated with that model; receiving a selected model from a user; generating a plan from the selected model, the plan comprising plan objects selected from the set of content objects obtained by the selected model according to one or more of the following: the rules, the constraints, and the equations of the selected model; producing an interactive presentation from the plan for presenting to the first user; receiving, from the user, a change directed towards one or more of the plan objects during the interactive presentation; determining a number of times the change has been made by other users; upon determining that the number of times the change has been made by other users exceeds a threshold, generating a new model based at least in part upon the changed received during the interactive presentation; and upon determining that the number of times the change has been made by other users does not exceed a threshold, revising the plan to include the change without generating a new model based on the changed. 20. The one or more computer storage memory of claim 18 having further computer-executable instructions stored thereon that cause the one or more processors to perform operations comprising: maintaining the new model as a model of the set of models; locating the new model for a second user; generating a plan from the new model; and producing an interactive presentation from the plan for presenting to the second user.