On the concept of implied threat:

Villian places a 75 chip bet, and has $300 remaining in his stack. Fnord raises his bet $200 into a 250 chip pot, making the pot $450, $200 to Villain, giving him a little better than 2:1 pot odds. However, it's really $300 to villain in a $650 pot, because Villain knows that if Villain pushes, Fnord is calling based on the ridiculous pot odds, and if Villain calls, Fnord is putting him in on the next street. So Fnord has just put out a $300 bet with 200 chips, making the situation much more precarious for the opponent.