There are so many great new BBM features that BlackBerry 10 has to offer. Among those features is the ability to view updates from your contacts. You can access the update stream within BBM by clicking on the three lines located on the lower left of the screen. This will bring you to the updates screen where you can view all of your contacts updates. Furthermore, you can update your status to show what your listening to by toggling on the "Show What I'm Listening To" slider from within the BBM options menu.
The problem with with the "Show What I'm Listening To" option is that it literally tries to show everything that you are currently listening to. So if your browsing YouTube it will update your status to that, and yes it also means that if your browsing that "special" site you haven't told anyone about its going to display that as well.
So to avoid some awkward chats with your friends or an interesting conversation with your spouse, it may be best to just turn that little feature off. To do that all you have to do is open up BBM, slide your finder down from the top to gain access to the BBM "Settings" icon and disable "Show What I'm Listening To". If you have done it correctly it should look like the picture below.