Latest GNOME 3.2 uses new shell extension syntax so “old” GNOME 3.0 extensions don’t work on Fedora 16 or UBUNTU 11.10 using GNOME 3.2
Even when you copy extension to your
/home/username/.local/share/gnome-shell/extensions folder extensions are disabled by default.
To enable them you need to use
gsettings command in terminal.
For example download, extract and copy email@example.com extension to your extensions folder.
Then enable extension with gsettings command:
gsettings set org.gnome.shell enabled-extensions "['firstname.lastname@example.org']"
If you are aware of GUI for enabling/disabling GNOME Shell extensions please share that info.