I decided it was time to put some of the new capabilities of Safari to work. Downloaded two extensions: Safari AdBlock (not to be confused by the plug-in with the same name and Invisible Status Bar. <
Here's where I got them>, but you can see there are at least four pages of extensions available as I write this.
Howsome ever, I couldn't seem to get Safari to accept them.
I
already had set the "Enable Extensions" menu in the Develop menu.
If you don't have that menu, you can't do the "enable" bit, of course. *See the last paragraph for the slightly less than intuitive instructions to get that menu as well as the "Extensions" tab in your prefs.
While the downloading was fine, the 'standard' install method did nothing but re-download the file (recognized by its ".safariextz" file name suffix). Tried the following:
1. Quit Safari and double-click the file.
2. Quit Safari and control/right-click the file and use the "Open" menu item.
3. Quit Safari and control/right-click and use the "Open with..." menu and specifically select Safari!
4. Quit Safari and ate dinner.
The only successful procedure was number four.
Out of shear desperation, I went to Apple's Forums.
Sure enough, there were plenty of people having the same problem. Also many 'helpers' confused about what 'extensions' were, what version of Safari could use them, where they are stored and several methods of installing them. Of course, there were also responses saying, "Thanks, that's exactly what I needed!" Except there were many more reporting that nothing had helped. I was just another one...
But, one thread gave the path to where they were stored ~/Library/Safari/Extensions. Well, guess what?! There weren’t no "Extensions" folder in that path on my iMac!
Others had mentioned a "Preferences" file in there, also. Not in mine. The only one for Safari was in the usual ~/Library/Preferences path. Anyway, with nothing to lose, I simply created the "Extensions" folder where some said it should be. And re-started Safari. Repeated steps 1 through 3 above. (Judy said she wouldn't help with number 4 until tomorrow night)
I wish I could report success, but nothing worked, yet.
Then I noticed that there was now an "Extensions.plist" in that folder I created! So, Safari must have noticed that things were a little different. Maybe if I manually move one of those two downloaded extensions into the folder Safari now 'sees,' it will also 'see'
that.
Quit Safari, move the file, re-start Safari: nada, no change.
OK, one last double-click and I'll forego Safari extensions. I double-clicked the file I downloaded and manually placed in the folder I created for Safari. Well, looky there! The much talked about, but never seen on this Mac dialog asking if I really, really wanted to open this file that appears to have come from the interwebs! "Well, let me think about that for another couple of hours...
OF COURSE I WANT TO OPEN IT!!! WHY DO YOU THINK I DOUBLE-CLICKED IT???!!! WERE YOU NOT AWAKE WHEN I DOWNLOADED THE THING A COUPLE OF HOURS AGO AND HAVE WORN SOME PIXELS OFF THE ICON BY DOUBLE-CLICKING A GAZILLION TIMES???!!!!! 
Well, to make a gruelingly frustrating problem shorter...it worked. whoopie.
*Now, to be able to enable the use of Extensions in Safari FIVE:
Open the Safari prefs
Click the Advanced tab
Click the "Show Develop menu" checkbox
Close the prefs window, if you like.
Now, in the just appeared Develop menu, select the "Enable Extensions" item.
The reason I've heard about this weird procedure is that the upcoming Extensions Store is not yet available and Apple wants to be the supplier for these things, of course. Even though they are all, so far, free/donation ware. Another reason is that Extensions are still a work in progress. I can certainly vouch for that, at least in the "let me use one" area. BTW, now that you have enabled Extensions, you will also have a new tab in the prefs labeled...
Extensions!
That will display some info about the Extension and, supposedly, allow managing them.
