13. A computer storage medium encoded with a computer program product for establishing a multimodal personality for an application that provides vocal and visual output, the computer program product comprising computer program instructions for, when executed by at least one processor: selecting, by the application that provides vocal and visual output, matching vocal and visual demeanors; and incorporating, by the application, the matching vocal and visual demeanors as a multimodal personality into the application by: selecting one or more demeanors from a store comprising a plurality of demeanors, the selected one or more demeanors defining the matching vocal and visual demeanors; linking one or more styles to one or more markup elements of a markup document output by the application based on the selected demeanor; and rendering, using a multimodal browser, the markup document using the one or more linked styles, the rendering comprising rendering at least one visual aspect and one speech aspect, wherein: selecting matching vocal and visual demeanors further comprises selecting a visual demeanor in dependence upon vocal aspects of a history of a user's navigation among multimodal web sites, the vocal aspects comprising one or more of: number of grammars per page; number of dialogs per page; dialog intensity; or number of speech inputs per page.
13. A computer storage medium encoded with a computer program product for establishing a multimodal personality for an application that provides vocal and visual output, the computer program product comprising computer program instructions for, when executed by at least one processor: selecting, by the application that provides vocal and visual output, matching vocal and visual demeanors; and incorporating, by the application, the matching vocal and visual demeanors as a multimodal personality into the application by: selecting one or more demeanors from a store comprising a plurality of demeanors, the selected one or more demeanors defining the matching vocal and visual demeanors; linking one or more styles to one or more markup elements of a markup document output by the application based on the selected demeanor; and rendering, using a multimodal browser, the markup document using the one or more linked styles, the rendering comprising rendering at least one visual aspect and one speech aspect, wherein: selecting matching vocal and visual demeanors further comprises selecting a visual demeanor in dependence upon vocal aspects of a history of a user's navigation among multimodal web sites, the vocal aspects comprising one or more of: number of grammars per page; number of dialogs per page; dialog intensity; or number of speech inputs per page. 16. The computer storage medium of claim 13 wherein selecting matching vocal and visual demeanors further comprises selecting a vocal demeanor in dependence upon visual properties of a history of a user's navigation among web sites.