Well if I recall right I believe I've been here since the game launched and was available to the public so I'm guessing January 6, 2011 was it's starting day since that's the date on my first account. Some of the old original staff had access to the game before the public did though and dates on their profiles are slightly older. Starting date was January of 2011 I believe though.
I remember it back in 2010?
FH has indeed been playable to the public for about 3 years although some say they've been playing it for 4 years...