Kudos to David Pogue for using his New York Times soapbox [1] to point out how the cellular carriers are padding their profits by adding short messages to voicemail greetings, to instructions for listening to your own voicemail, and so on. Sure, it's only a few seconds, but when you multiply that by all the times you listen, it adds up. And when you multiply all the times it's heard by all the cellular subscribers in the country (and indeed in the world), you can see how increasing call time by just a little bit can result in real money - our money - for the carriers. (Also be sure to read his followup post.)
This isn't a conspiracy theory - cellular carrier executives have admitted this fact to Pogue. What can we do? Complain en masse. If the customer revolt is loud enough, perhaps the carriers will back down from these policies. Pogue assembled the following links to the four major U.S. carriers; I encourage you to complain to at least the one that's billing you each month.
At least the iPhone does away with the extra messages; according to Pogue, Apple insisted that AT&T drop the pre-beep message for those using the iPhone.
[1]: http://pogue.blogs.nytimes.com/2009/07/30/the-mandatory-15-second-voicemail-instructions/
[2]: http://www.verizonwireless.com/b2c/contact/index.jsp
[3]: mailto:customerissues@attnews.us
[4]: http://community.sprint.com/baw/community/buzzaboutwireless/general/rants-and-raves?view=discussions
[5]: http://forums.t-mobile.com/tmbl/board/message?board.id=General&thread.id=2346