Methods and arrangements involving portable devices, such as smartphones and tablet computers, are disclosed. One particular arrangement concerns a software program that is launched following detection of audio content performed by a first musical artist. A phone can be provided with plural such software programs, tailored to respond to different types of detected content. Another aspect of the disclosed technology enables a creator of content to select software with which that creator's content should be rendered—assuring continuity between artistic intention and delivery. A great variety of other features and arrangements are also detailed.