*gnome-shell-gnome2-notifications is YAGSE (Yet Another GNOME Shell extension) that tries to provide an "old-skool" gnome2 way of showing applications.

Most of the applications tray icons (in fact, all of them but some applets) are now located in the notifications area in GNOME Shell instead of being located at the old traybar. This could be annoying since this area is hidden by default and you won't be able to see easily if any icon is trying to communicate something. You'll have to make the notifications area appear. Pidgin is the best example for me. It was the main reason for me to develop this extension, I wasn't noticed when I had new message. Icon was blinking but it was hidden!