noun: Belongs to the same general family as the common Internet troll, poseur, forum whore, etc. Infrequently used as verb ("board warrioring").
1. Someone on a message board dedicated to a certain activity who spends almost all of his/her time posting on the board and very little of it (if any) actually participating in the activity in question.
2. Someone on a message board dedicated to a certain activity that would rather get on the board and argue with other people about who is better at the activity than actually do the activity and find out.
Board warriors are most commonly associated with computer game forums.
<rasputin> haa anyone ever seen sirbruce logged in?
<boog> Hell no, he's a total board warrior