There are a lot of news about facebook privacy lately, from f8 “like” feature to their apps/chat bugs. We can see these reports from google’s employees who explain how to delete facebook profile (may be they have their own reasons, but it is still true). Seems like everybody wants to ignore your privacy as much as possible, and the truth is that nothing is really private. As a matter of fact, I have been ignoring privacy policies myself and always assume that nothing is really private. In ad driven world many companies still use private data to target users in a better way.
Anyway, it applies to forums, instant messengers, email, even phones to some extent. May be I am a bit paranoid, but I just treat everything with the feeling that someone may be watching. Just be careful saying things that you wouldn’t say in public no matter where it is.
As for important conversations, I prefer in person meetings over any other. If it’s not feasible, phone and skype are my best options. I still do im for the issues that don’t matter much. Whenever you have something important to talk about, just choose the source wisely.
Here is a good old school song for you