I was horrified to find that PithHelmet was broken under the new Safari too. But - the author's already posted an update and it works...at the moment you can grab it from here. You have to install it manually though - go to ~/Library/InputManagers/SIMBL/Plugins and replace the PithHelmet.bundle with the version you downloaded above. If you deleted the SIMBL folder, presumably you can install an older version of PithHelmet to get it back...anyway it worked for me. Goodbye advertising. HAHAHA.