inhibit-startup-echo-area-message

inhibit-startup-echo-area-message is a variable defined in `startup.el'.
Its value is

nil

Documentation:
Non-nil inhibits the initial startup echo area message.
Setting this variable takes effect
only if you do it with the customization buffer
or if your init file contains a line of this form:
(setq inhibit-startup-echo-area-message "YOUR-USER-NAME")
If your init file is byte-compiled, use the following form
instead:
(eval '(setq inhibit-startup-echo-area-message "YOUR-USER-NAME"))
Thus, someone else using a copy of your init file will see the
startup message unless he personally acts to inhibit it.

You can customize this variable.