This is a treacherous move. White invites the opponent to play the classic plan with h6-g5, leading to a sharp position.
1. e2e4  1... e7e5  2. g1f3  2... b8c6  3. f1b5  3... a7a6  4. b5a4  4... g8f6  5. d2d3  5... f8c5  6. c2c3  6... b7b5  7. a4b3  7... d7d6 