You could have done it like this:
Welcome, all Mac users and fans, to our newest forum. We encourage you post all your problems, questions and comments about Macs here. We hope ut us going to be useful to people.[.. blah, blah, blah, yada, yada, yada]
That would have made it more official, but...
As StevenC said it: You're not so special! ;) :)