- Turn the history off for a conversation (say, on a Windows box);
- Type a phrase;
- Reboot into Linux (or maybe just reboot);
- Start a browser, go to GMail;
- Open the conversation with the same person;
- Oops... the phrase is still there.
In other words, what had at least a pretense of implementing the Off the Record protocol, now doesn't even make an attempt to pretend.
So, folks, just like the XX century saying goes, "Don't ever say in IM something you don't want to see on CNN".
Hello, encrypted XMPP.