This is an oldie but a goodie, and something I wish we could do in Firefox: in Safari there's only so much room on the Bookmarks bar, but instead of writing shorter and more confusing names in order to fit more in, you can use a font trick to display meaningful little dingbats for your Bookmarks instead. For details, check out this old post from Merlin over at 43 Folders.

Update: Over at TUAW, C.K. has written a full tutorial on this technique. Check it out!