Default browser. From MozillaZine Knowledge Base The term "default browser" is used to describe the URL and file associations that determine which web browser is launched when you open an Internet shortcut or HTML file or when you click a link in a mail application like Thunderbird or Outlook Express, if you have more than one web browser installed on your system.
Note that MSN Messenger and other applications may be "hard-coded" to open Internet Explorer, no matter which browser is set as the default. Also, Internet service providers like PeoplePC Online, Juno and NetZero may provide connection software that automatically launches Internet Explorer. All systems. Help / FAQ / Quick Add. IE6 No More - Home. Firefox Extensions.