11. A method comprising: receiving a natural language input from a user of a network accessible device; identifying a sequence of keywords conveying a message communicated in the natural language input; analyzing the identified sequence of keywords to identify a scenario among a plurality of scenarios, each of the scenarios representing a category of user messages; selecting a plurality of segments in the database based on the sequence of keywords and the scenario; retrieving the selected segments from the database; and combining the retrieved segments to generate an on-the-fly presentation.
11. A method comprising: receiving a natural language input from a user of a network accessible device; identifying a sequence of keywords conveying a message communicated in the natural language input; analyzing the identified sequence of keywords to identify a scenario among a plurality of scenarios, each of the scenarios representing a category of user messages; selecting a plurality of segments in the database based on the sequence of keywords and the scenario; retrieving the selected segments from the database; and combining the retrieved segments to generate an on-the-fly presentation. 12. The method of claim 11 , in which the presentation comprises an audio/video (A/V) presentation as part of an advertising campaign, the A/V presentation relating to an experience of the user as expressed in the natural language input.