(AddThis Happiness Specialist)
Mar 19, 2012 10:53AM EDT
Hi, I'm the developer of the Safari extension. Sorry for the delay. Let's see what the problem is. Please check Safari (menu) -> Preferences -> Extensions (tab). Do you see "AddThis" in your list of extensions? If you don't, then AddThis hasn't been installed yet, so try re-downloading the extension (http://www.addthis.com/tools/safari), and double-click on the file you download.
If you DO see "AddThis" in your list of extensions, please select it and see if you have "Enable AddThis" checked. If not, please see if checking "Enable AddThis" solves the problem.
Please let me know if either of those solutions work, or if we have yet to solve your problem.