I have a Russian translation of Bobby Fischer's My 60 Memorable Games. In the Game 1 (http://www.chessgames.com/perl/chessgame?gid=1008366) in the annotations given after Black's
4. ...Ng8-f6 the author writes that
4...d5 5. Nbd2 Bd6 6. Bg2 Nge7 7. 0-0 0-0 8. Nh4!
[fen ""] 1. e4 c5 2. Nf3 e6 3. d3 Nc6 4. g3 d5 5. Nbd2 Bd6 6. Bg2 Nge7 7. O-O O-O 8. Nh4
results in White's initiative. I think that
initiative means creating direct threats to which the opponent must respond immediately. But where is initiative after
Nh4? White doesn't seem to create any direct threats at all