I wrote this so I wouldn't lose track of interesting areas of extremely long pages. This extension will let you dog-ear parts of a page so you can move on without fear of being unable to find them later. Marking a spot will place a digit, starting with 1, on the page. You can then quickly return to these marked areas by using a hotkey (Shift+Spacebar) or by clicking the status bar icon.
Firefox 2 and up will save your dog ear locations for individual URLs.
Please note that using Shift+Click to mark the page will not work if you are clicking directly on text. This is intended to avoid conflicts with the Firefox default action of highlighting text.