I run into people all the time that don’t realize their tweets are public. They think it’s a closed system between them and their followers. If someone else jumps in the conversation, they’re often surprised… I have seen several instances where they then tweet "how did you see my messages?"
The fact that Facebook defaults to friend-to-friend messages and Twitter defaults to friend-to-everyone is lost on most people. It’s much like open wi-fi networks. It’s a lack of education in general. Much of this is because the technology and the tools are so new – but much is also due to the "personal" feel of Twitter.
If there’s one thing Twitter does well, it’s create the sense of a "conversation" between people. You feel like its just you and your followers, and it’s easy to forget, whether through misplaced comfort or outright ignorance of how the technology works, that your messages are out there for all to see.
The best social media technologies are those that make people feel comfortable. Those are also the ones that, if not sufficiently understood, can be most dangerous. Once information is out there it can’t readily be reeled back in.
