Well, it's Seinfeld, so it would have been hacked or otherwise malfunctioned to make the show entertaining. "Jerry, these kids won't leave me alone!" or "Jerry, this woman keeps leavin' me messages, and I get all wowwowah". Didn't mean to cast aspersions on how it actually works.
Maybe you should aim higher or broader...take the ability to leave messages for people and do something with that? I just don't find the idea very compelling - it's too narrow feeling. If I want to hear a friend, I want to hear from them whenever it is, not just in the morning. And if I want a fancy alarm clock thing, I simply want one that I can load ogg or mp3 files in. Messages from people might be loaded or automatically pulled in, but for me that's just not a central feature. Another thing that sort of limits its appeal is that you have to have your computer in your room with you, and on. Mine has an option to automatically wake up, but it's a fiddly bios thing that most people aren't going to want to use, and most people don't like sleeping with the things on, either - they're noisy.
So, beyond what I don't like, I wonder how you could take what you've created and tweak it to appeal to other audiences, or be useful in other ways? If you've got good tech behind it, perhaps it's just a matter of trying out a few other niches - maybe something else is what it's really destined to be.