The '.netrc' file is used by the FTP program to automatically log a user into an ftp server without prompting the user for their username or password. This is particularyly useful for anonymous login sites if your often log into these type of sites. 
#.netrc
	machine ftp.machine.org login PASSWORD
	machine ftp.ftpserver.com login PASSWORD
	default login anonymous password user@site
     The default will match any machine not listed in the entrys above. That will usually be an anonymous ftp server. If, however you want to log into a machine not listed but have an account and don't want to use the default anonymous login specified above, you will call the FTP program with the flag '-n' flag which specifies not to use the '.netrc' file.
	% ftp -n ftp.hostname.com
	> user USERNAME PASSWORD
The following information is from the 'ftp' manual (man ftp):
THE .netrc FILE
	The .netrc file contains login and initialization information used
	by the auto-login process. It resides in the user's home directory.
	The following tokens are recognized; they may be separated by spaces,
	tabs, or new-lines:

	machine name
		Identify a remote machine name. The auto-login process
		searches the .netrc file for a machine token that matches
		the remote machine specified on the ftp command line or as
		an open command argument.  Once a match is made, the
		subsequent .netrc tokens are processed, stopping when the
		end of file is reached or another machine or a default token
		is encountered.

	default
		This is the same as machine name except that default matches
		any name. There can be only one default token, and it must be
		after all machine tokens. This is normally used as:

			default login anonymous password user@site

		thereby giving the user automatic anonymous ftp login to
		machines not specified in .netrc. This can be overridden
		by using the -n flag to disable auto-login.

	login name
		Identify a user on the remote machine. If this token is
		present, the auto-login process will initiate a login using
		the specified name.

	password string
		Supply a password. If this token is present, the auto-login
		process will supply the specified string if the remote server
		requires a password as part of the login process. Note that
		if this token is present in the .netrc file for any user
		other than anonymous, ftp will abort the auto-login process
		if the .netrc is readable by anyone besides the user.

	account string
		Supply an additional account password. If this token is
		present, the auto-login process will supply the specified
		string if the remote server requires an additional account
		password, or the auto-login process will initiate an ACCT
		command if it does not.