Odd text before ":" in Terminal
That is your computer's hostname. In Terminal type the command hostname and that is what you'll see. You can change the host name with the command sudo scutil --set HostName desired-host-name. There are some networking scenarios where this won't permanently fix the problem, though. (e.g. OS X assumes hostname of other network computer: how to prevent this?). It happens with my machine at work (on a Windows domain). Aside from being a little disconcerting, there are no functional repercussions that I've experienced.