Is there a plausible way to spread disinformation about your activity, such that if anyone ever brought up your past electronic activities you could show that there's no way to tell what's a true record and what's just random shit created by some service?
I wasn't thinking about secrecy, but about false openness. For example, having eight Facebook accounts, and (somehow) making sure your trusted friends knows which is the real on, while each of them present a different personae. Decoy sites, suppose.
No, it's not open to government monitoring, unless of course they have the ability to break "unbreakable" encryption. And, if they do manage to magically brute force a single key, they only get a single message decrypted. Each message uses a different key, so compromising a single message doesn't compromise the whole conversation.
For a school project I (sorta) implemented this on Android 1.5 two years ago. I stopped before finishing the key rotation stuff, so ended up with just a encrypted text messaging client. Another company just recently announced an OTR text message program for android, you should look it up! Textsecure by Whisper Systems.