Commands like
(defun browse-url-firefox (url&optional new-window)
"Ask the Firefox WWW browser to load URL.
Default to the URL around or before point. The strings in
variable `browse-url-firefox-arguments' are also passed to
Firefox.
Should (optionally, enabled by default) put in their prompt,
(interactive (browse-url-interactive-arg "URL: "))
some indication of which program they are about to call.
E.g., instead of URL, say "Call firefox on:" or "Firefox:" or
"URL for Firefox:".
Why? Because otherwise it looks just like the w3m-view-this-url etc.
default prompts, even if one knows which function he is calling.
(emacs-snapshot package, version 1:20101030-1)