From MozillaZine Knowledge Base
Note: This preference will be removed and search preferences will be consolidated in Firefox 23 (bug 738818).
When entering information in the Location Bar, Mozilla attempts to convert the information into a usable URL. For example, “mozilla.org” is automatically converted to “http://mozilla.org/”. When Mozilla is unable to discern what URL the user wanted, the information that was entered may be submitted to an Internet Keywords service. This preference determines the Internet Keywords service URL.
Possible values and their effects
Any valid URL may be specified. The keyword will be appended to the URL and then the user will be redirected to the new URL. The default value is:
In most Mozilla products; in Firefox and Sunbird the default was:
Recent versions allow this value to be localized.
Replacing Google with other search engines for location bar search
If you are not a fan of Google, you can replace it with another search engine, for example, Scroogle or Bing. Note that these give 'regular' result pages, whereas the default Google string directly sends you to the most likely result if it deems the query unambiguous.
Go to about:config, find the keyword.URL preference, context-click (right-click) the preference name, select Modify and enter a new value. It is much like using a keyworded bookmark for a search, except the query is appended at the end whereas keyworded bookmarks replace %s with your query.
First checked in
Has an effect in