It was already possible to listen in on someone's conversation. In fact, not only was it possible, but it was very easy. They couldn't notice that you were listening, so you didn't have to stay out of the way.
Now, if the participants notice you, they will stop their conversation, tell you off, and you will have to find the information some other way. If you even can.
EDIT AGAIN: so we finally decided to start a devlog, which for whatever reason feels like a pretty good thing, so it'd make me feel good if you'd go take a look at http://forums.tigsource.com/index.php?topic=47030.0 thanks(:
Couple new editor features, not shown, but I put (most) every single gif from day 01 into a gallery you can admire: http://imgur.com/a/9ffMn
Edit: ok fine, gif of new tools, but you should still look at the gallery.