Thinking about Future Tech. Other cool things that are potentially down the road. On my Motorola Droid I've been experimenting with speech to text. The accuracy is actually quite good! Getting better all the time. These applications have the ability to "fine tune" themselves so that the transcription gets better and better.
Eventually I would imagine that there would be software that would run on your phone, in the background, and could automatically transcribe everything it hears, convert it to text, and save it to "the cloud" for archiving and searching. I would imagine you could "tag voices" in the web interface the same way we tag photos in Facebook. Imagine being able to reference a conversation you had with a friend last week? Or being able to search all of your conversations for search terms? Would be handy for settling arguments, for sure. Great for meeting minutes. The algorithm could eventually learn who's talking and tag them automatically.
If you think about it, all of the technological capabilities are there. Software can run in the background. Software can translate speech to text. Software can upload text to a server (low bandwidth). Software can distinguish between voices. Software can course correct on itself. Software has advanced text searching capabilities (see gmail).
I'm actually surprised Google Voice doesn't already give you the ability to save all of your voice phone calls as text. It already translates voice mail to text, so the technology is in place. As far as privacy, speaking is just another means of communication. We email, we SMS, we talk on the phone, we instant message. Talking face to face is the only method of communication that doesn't give us the opportunity to "save for later reference" — The technology to record phone calls does exist. My Palm Centro did this and that was 3 years ago. I propose the only reason we're not capturing our face to face conversations is because the technology hasn't been invented yet, except it has, and just hasn't been put to good use yet.
It will be interesting to see if it ever is.