Yeah? Not 6th? I'd better go get my present.

EDIT: I don't know... the first post to the coffeehouse was 4/7/2004.

EDIT 2: According to the following table, user registration jumped on 4/6/2004, so, I think that's the Grand Opening.

PS. Most of the users joining prior to 4/6/04 are MS people.
                                                                                                                                             

Users Join Date Count
      Join Date       Total
    4/1/2004     60
    4/2/2004     15
    4/3/2004     2
    4/4/2004     1
    4/5/2004     15
    4/6/2004     1070
    4/7/2004     1047
    4/8/2004     395
    4/9/2004     191