No, systray icons are displayed (and can be accessed and interactively used) in the bottom right corner, which is, however, shown only when you push your mouse

No, systray icons are displayed (and can be accessed and interactively used) in the bottom right corner, which is, however, shown only when you push your mouse cursor there, or when some notification shows up. The area left of the username (right top corner, no idea how it's called) is available only to the gnome-shell extensions that you have to install and turn on/off. I like it, though there are some problems, like quite often missing Empathy IM notifications (given that we use jabber quite a lot in the work...).