Listening to MP3's and other audio in Safari
Are all of you saying that linked MP3 files in Safari under Mac OS X, such as the AppleVis podcasts, download instead of streaming within the browser when you activate the link? That's not the case for me. Most posters to the macvisionaries list ask about how to force an MP3 file to download from the link instead of automatically playing from within the browser. Cliff, has this behavior of downloading instead of playing MP3 files in Safari always been true on your Mac? If you open Safari from another user account, do you also find this? (I create at least one alternate account on my Mac for testing purposes.)
It sounds to me as though you've installed some kind of Speed Download app that is forcing this behavior in your account. If you navigate to the "Help" menu on the Safari menu bar, and select the "Installed Plug-ins" option, what gets listed for your account?
If clicking on an MP3 link from Safari in your fresh user account plays the MP3 file in the browser, then there's some local configuration of your Safari account that is keeping this from happening. This is likely to be either due to a plug-in or browser extension that you installed. I was wondering whether you had installed some sort of speed download plug-in, which is why I had you check your installed plug-ins for something with a name like that. Most of the plug-ins like the ones for QuickTime are ones that you'll need, and you'll find that they're present if you check the installed plug-ins for Safari on your new user account, too.
The answer to your question about how to check whether there are specific installed plug-ins for your user account and how to remove them, is that these are stored in a Library/Internet Plugins folder under your account. Under Lion and Mountain Lion, by default, your account and your system's Library files are hidden from the user in Finder. That means that you can navigate to those locations in Finder, if you know where they are, but they won't be shown to you by default, to keep you from deleting or changing some important files by mistake. That's why I had you check the installed plug-ins from the Help menu instead. Although there's a long list of installed plug-ins, I figured you would notice if you had something with the name of "download" showing up there.
Yes, you can wipe your current Safari preferences and set them back to the default values if you have to. That's contained in a .plist file under the Library/Preferences folder for your account -- another hidden file. But first let's check whether one of your extensions or your browser configuration is responsible for the behavior. From Safari, bring up your preferences menu with Command-comma, then select the "Extensions" tab from the title bar. If you have any extensions installed and enabled, you should be able to set the switch to disable them from this pane. If you don't have extensions enabled, then go to the "Advanced" tab in your preferences title bar. You should be able to navigate from the pane contents to the title bar directly with Control-F5, then VO-Right arrow or Right arrow or tab to "Advanced" and select it with VO-Space or by simultaneously pressing your up and down arrow buttons in QuickNav mode, then tab into the pane. I'm guessing that you have the box for "Show Develop menu in menu bar" checked? If you have extensions installed and disabled them on the "Extensions" tab, close your preferences window with Command-W and then try activating a podcast link. If it still downloads instead of playing, we can check the "Develop" menu on your Safari menu bar to find out your "User Agent" setting. If the podcast plays in the browser, we can figure out which (if any) of the extensions you had enabled is the problem. If that didn't work, we can look at the plug-ins under your Library/Internet Plugjns folder. Finally, if we have to, we can delete your Safari preferences file.
HTH. This is usually the kind of trouble-shooting that would get handled on a mailing list.
If you haven't done any special configuration of Safari, then you may not miss your Safari folder. But, for example, any bookmarks you may have saved were stored in a Bookmarks.plist file under your user account's Library/Safari folder that you deleted, and those are now in the Trash. You probably still want those. There are also plist files for you browsing history, default search engine configuration, and a few other items that you may not miss. If you set up certain local features, such as reader services that use cached space in your browser, they may also have configuration information here. The problem is that these kind of walk-through instructions are usually handled on mailing lists, where the notifications are faster, and where there are other users to step in when there are delays in reponse. It also depends on what you need to keep, and there's a kind of "First, do no evil" philosophy in providing fix-it step. I can tell by now that you're pretty comfortable with advanced concepts.
I'd suggest closing Safari, putting things back the way they were (getting the folder out of the Trash and moving it back to replace the new folder you created), and doing a less extreme fix. As I stated before, usually the problems can be traced back to an installed plugin, which would show up under your account's ~/Library/Internet Plug-ins folder (note the hyphen in "Plug-ins" -- I'm not sure I spelled it correctly earlier), or it could be in an enabled Safari Extension, which you can either disable or remove from the extensions pane of your Safari preferences window. Apart from this, the less extreme action to "start afresh" is to delete the preference file responsible for most your selections. Again, usually even for that step we recommand that you close your application, then move the ~/Library/Preferences/com.apple.Safari.plist file to your Desktop or other location instead of outright deleting it. Then start up Safari, which will open without having any configuration preferences associated with it, just as though it were a new account -- except that you'd still have access to all your bookmarks, browsing history, etc. If that solves your problem, fine. If not, you can always close Safari and move back your old com.apple.Safari.plist file back to the original location. The reason for closing Safari is that the preference file associated with an application gets opened, and updated, each time you open and close an application. If you moved a copy of a plist file back while the application is open, the settings would simply be overwritten when you closed the appplication with whatever values were currently in effect. On the other hand, if you open an application and there is no preference file present, your system will create a new one with all the default values. Hope this makes sense.
Good luck however you decide to proceed.