No, this wasn't the first one. There were two threads already up by the time I hit the Post button on this one:
http://www.freerepublic.com/focus/f-news/520255/posts
http://www.freerepublic.com/focus/f-news/520260/posts
And then there must have been a thousand threads started after that, all throughout the day. You can do an archive search on "World Trade Center" (with "match all words"), to see some of them.
I know it sounds melodramatic, but that's exactly what happened.
I just finished baking the brownies to take to the fire station down the street.
My family has done this every year for the past four years...a card of appreciation and some sort of warm baked good thanking them.