Fortunately you can undo that in firefox (separate boxes -- ctrl-l for location, ctrl-k for search, and disable the "search if not a url" option), but it's not

Fortunately you can undo that in firefox (separate boxes -- ctrl-l for location, ctrl-k for search, and disable the "search if not a url" option), but it's not the default, and that leads to more and more people using bing to search for google to then search for facebook, as they have no concept of the idea of a URL (or indeed a program, a file or a directory) :(