The subject disclosure is directed towards a web service that maintains a set of models used to generate plans, such as vacation plans, in which the set of models includes models that are authored by crowd contributors via the service. The models include rules, constraints and/or equations, and may be text based and declarative such that any author can edit an existing model or combination of existing models into a new model. Users can access the models to generate a plan according to user parameters, view a presentation of that plan, and interact to provide new parameters to the model and/or with objects in the plan to modify the plan and view a presentation of the modified plan.
Please help me write a proper abstract based on the patent claims. CLAIM: 1. In a computing environment, a system, comprising: an authoring tool configured to allow an author from among crowd contributors to author a new model, the new model containing rules, constraints or equations, or any combination of rules, constraints or equations, by which the model is configured to generate a plan comprising plan objects; and a presentation mechanism configured to produce a presentation based upon the plan objects. 2. The system of claim 1 wherein the presentation mechanism is coupled to a user interface of the authoring tool. 3. The system of claim 1 wherein the authoring tool and presentation mechanism are incorporated into a hosted web service or set of hosted web services. 4. The system of claim 1 wherein the new model is based upon an existing model, and wherein the existing model and new model contain only text data. 5. The system of claim 1 wherein the new model is based upon an existing model, and wherein the existing model and new model are declarative. 6. The system of claim 1 wherein the new model is based upon an existing model, and wherein the authoring tool is configured to allow authoring of the new model based upon the existing model by modifying text from the existing model, or adding to text from the existing model, or by both modifying text from the existing model and adding to text from the existing model. 7. The system of claim 1 wherein the new model is based upon an existing model, and wherein the authoring tool is configured to allow authoring of the new model based upon the existing model by combining text from the existing model with text from another existing model. 8. The system of claim 1 wherein the new model is coupled to a search mechanism that provides content objects, and wherein the new model uses the rules, constraints or equations, or any combination of the rules, constraints or equations to generate the plan comprising plan objects. 9. The system of claim 1 wherein the new model is selected by a user and used with user input data to generate a plan for the user that includes plan objects selected based at least in part upon the user input data, and further comprising, a user interface by which a user experiences the presentation produced by the presentation mechanism. 10. The system of claim 9 further comprising, an interaction mechanism configured to allow one or more changes to the plan objects, the presentation mechanism configured to generate a new presentation based on the changes to the plan objects. 11. The system of claim 1 wherein the new model is selected by a user and used with user input data to generate a plan for the user, and further comprising, an interaction mechanism configured to allow one or more changes to the input data by which the model generates a new plan comprising a different set of plan objects, the presentation mechanism configured to generate a new presentation based on the different set of plan objects. 12. The system of claim 1 wherein the presentation mechanism comprises a content synthesizer that processes the plan objects into a linear narrative. 13. The system of claim 1 wherein the presentation includes a timeline, a calendar, a schedule, a presentation, a list, a gallery, or a map, or any combination of a timeline, a calendar, a schedule, a presentation, a list, a gallery, or a map. 14. In a computing environment, a method performed at least in part on at least one processor, comprising: maintaining a set of models, each model comprising rules, constraints or equations, or any combination of rules, constraints or equations, by which that model generates a plan comprising plan objects; providing access to a selected model for authoring a new model therefrom, including allowing content of the selected model to be used for editing into the new model, or combined with content from one or more other models into the new model, or both used for editing into the new model, or combined with content from one or more other models into the new model; and maintaining the new model as a model of the set of models. 15. The method of claim 14 wherein maintaining the set of models comprises operating a web service or set of web services, and wherein providing access to the selected model comprises interacting with an author via the web service to select and view content of the selected model. 16. The method of claim 14 further comprising, locating a selected model from the set of models based upon author or user input data. 17. The method of claim 14 further comprising, authoring another new model from the new model, including allowing content of the new model to be used for editing into other new model, or combined with content from one or more other models into the other new model, or both used for editing into the other new model, or combined with content from one or more other models into the other new model. 18. The method of claim 14 further comprising, locating the new model for a user, generating a plan from the new model based upon the new model and user parameter input, and producing a presentation from the plan for presenting to the user. 19. One or more computer-readable media having computer-executable instructions, which when executed perform steps, comprising, maintaining a set of models including models authored by crowd contributors, each model comprising rules, constraints or equations, or any combination of rules, constraints or equations; providing for user-selection of a selected model; generating a plan from the selected model, the plan comprising plan objects selected according to the rules, constraints or equations, or any combination of rules, constraints or equations of the selected model; and producing a presentation from the plan for presenting to the user. 20. The one or more computer-readable media of claim 19 having further computer-executable instructions comprising, receiving a new model from an author via a web service, and adding that new model to the set of models.