God bless the internet.
I have been on a Job Quest. Recently, I found a positions to my liking and was about to apply. I had done the research, visited in person, and just completed a shiny new resume. I was feeling confident.
But wait, your personal worth summary (resume) needs an introduction. I needed to write a cover letter. However, this application was being submitted to a national HR department and 'Dear National HR Department' is not the proper way to address a letter. I guess I'll just title it 'To whom it may concern'.
But a voice in my head, my guardian angel perhaps, said "Google that."
I googled some help on cover letters and there was one consensus: all people who title their cover letters 'To whom it may concern' are the scum of society. This was a faux pas so deadly it would blacklist me from any employment, ever, anywhere. I deleted the crime and contacted the offices for further details.
When in doubt, use the internet. If still in doubt, look at the newest page of Time Cheetah. That should set you at ease.