If there's anything as annoying as public radio and television pledge campaigns, it's political campaign ads sprouting up on the airwaves every Fall. I know they work to sway the undecided voters, but for those of us who have their minds made up (for some time now, actually), they are a waste of time and money.
Couldn't a subscription model work there too? Once you've decided you don't need any more of the arguments they are proposing, really and truly for sure, you could flip a setting on your TV and radio and telephone and be spared any further pitches.
Maybe we could arrange things that the act of switching the setting actually registers your vote ahead of time absentee-style. That way the political interests would know for sure that there is no point bombarding you any further, since you have already made your choice, October/November surprises or no. So making your selection would have to be done only when you have a feeling of ironclad commitment, also telling the political powers that there is also no point in appeals to you attempting to affect the voter turnout (the second main function of political ads).
In order to get people to keep their minds open and to not opt-out, advertising consultants would have an incentive to make their ads interesting to watch and creative, the same way other advertisers have. The undecideds might want to withhold their commitment in order to enjoy the play of ideas and issues right up until Election Day. This, I think, would also be a good thing as something to help counteract voter apathy.