Childish? Maybe
I don't think it is childish. I sometimes send trash talk to my opponents before games and I usually try to start up some discussions in the league forum. I personally would enjoy this kind of thing if ever we get to play. ;-)
As for joining the NT discussion, you just have to look at The_Mogul. As far as I know, he does not have a U21 or NT player, but he was very active on the NT forum last season. He is actually still really active on the U21 scene. On the other hand, if it is not your cup of tea, I understand. But it is a great way to learn about tactics and to see what works or what does not work in BB.
Run of the Mill Canadian Manager