The Feature has a post about the decrease in the voicemail feature of mobile phones.
 Although society is now becoming accustomed to time shifting entertainment, it is becoming less tolerant of doing the same with communication.Voice is still the killer application on mobile phones but, especially with younger generations, it may not be the sound of voice that is driving its success. A new study sponsored by Mobeon, a company which delivers messaging servers, has found that there is a growing generation gap between voicemail users and those who opt to send a text instead. When younger generations are faced with a an outgoing message, they often hang up and send a text, or they skip the call altogether and send a text message to begin with. Older generations, especially those who grew up with answering machines and other asynchronous communication, don't mind leaving a message. (...) The clarity of a text message is superior to that of a voice message in most cases. However it seems that more of the arguments in favor of text messages these two companies have found all exploit the fact that an SMS comes directly to the recipient's handset.
At work, in two years, I used 2 times my answering machines and the two times I had to ask the administrator for my passsword.