Remove username from terminal title

Your username is coming up in the Terminal title, because when you launch Terminal it is starting off in your home directory as the current "working directory."

There are two ways to do this:

1) Yosemite and earlier

a) You can create an AppleScript that launches Terminal and sets it Window title

tell application "Terminal"
   activate
   set custom title to "This is my Custom Title"
end tell

b) You can set it using bash's PROMPT_COMMAND variable in .bashrc. For instance, you can add the line PROMPT_COMMAND='echo -ne "\033]0;This is my custom title for ${HOSTNAME}: ${PWD}\007"'

Every time you open terminal, it will set that as your window title (assuming you are running bash, of course)

There's more info on using this method from this post: https://superuser.com/questions/79972/set-the-title-of-the-terminal-window-to-the-current-directory

2) In El Capitan forward:

You can turn it off by deslecting the "Display Working Directory" option in Terminal preferences.

The change is immediate, you don't need to relaunch Terminal; your username will no longer show on the title of the window