Firefox by default has a so called auto complete feature which searches for
urls that have been typed in or accessed in the past when the user begins to type a url. While this feature is mostly a time safer it nevertheless begins to pile up a large amount of urls which make the process rather messy.
The Autocomplete Manager brings light into that chaos. Two of the most interesting features that it offers is to sort the list of urls differently. You can sort it to display the most frequently or most recently visited urls first or select to begin with top level pages first.
Another feature I like is that you can change the amount of suggestions that are shown, place bookmarks first, only consider typed in urls or add and remove history entries. If you do use the auto complete feature you really should take a look at this extension and install it on your
computer.
Read More: Autocomplete Manager
via
Cybernet News
Firefox Autocomplete Manager 
Linear Mode
