The future is voice messaging, not voice mail. Voice messaging only comes into its own when matched with "presence" applications like Skype. It's an important distinction, for voice messaging will be used differently.
Links in the forums and some recent press comment around Skype have included reference to voice mail. It's probably a natural reference as we talk about "left a" and "getting voice mail" all the time. However in Skype's case what they are soon to implement is not really voice mail. Rather it is voice messaging. It's a subtle yet significant difference and I hope their language comes to reflect it.
Voice Mail is typically a voice message that was left when there was a communications failure. The intended recipient either wasn't near the phone or didn't want to answer your phone call. You leave a voice message you have no sense of timing. We call this telephone tag.
By contrast the "voice messaging option" on Skype doesn't require that you try calling the person first. You have their presence, you know at what level of importance you want to put the interruption. In this world the voice messaging function is different. A voice message is less invasive, less disruptive to workflow.
As a long time user of Skype I seldom get "out of the blue" calls. If I do, these calls are from people not on my buddy list. Frankly it is better they all go direct to a voice mail preferably with a different message from the one I leave my buddies. The message for the "unknowns" is probably no soliciting, state your business etc. If you pass these hurdles etc. and it is important then text me.
Thus for the most part my buddies text first. As they / we have a crude sense of each others presence there is no need for failed voice mail. Most dialogue starts with chat. It may or may not escalate to voice. Thus voice mail is for the most part superfluous. More importantly forcing me to leave a voice mail when I know they are there is a little silly. Messages aren't supposed to play tag by design. Thus the context changes from voice mail to voice messaging.
I probably haven't made myself clear. Coming up. Send a Skype voice message without ringing the other person's Skype client. That is a major difference to the telephone.
In Skype, voice messaging is for the occasions when I don't want to interrupt someone's workspace. It's perfect for update messages, invites to the weekend party etc. Messages that will benefit from a vocal / personal touch. Yet they don't have to interrupt the work flow. Let's face it... if I work with someone all the time and they aren't on Skype, then leaving a voice mail isn't the best place to try and reach them or deal with an urgent problem. I either have to now deal with it myself, postpone until we are mutually present (text can work well here) or call their cellphone.
Voice mail implies dump it in a box. Voice messaging heralds in a new more efficient age. Voice mail shouldn't be in Skype's vocabulary. Similarly the current "test" recorded message should be re-scripted to reflect the changed paradigm. It currently refers to voice mail. However you would have to know a tester to have tried it.