Not a WC person, but blitzing means chaining attacks together one after another, generally moving forward, forcing your opponent to retreat and hopefully overwhelming him.
The pros are that a good blitzer can be very difficult to defend against, especially if you're inexperienced. The constant attacks can make the opponent forget about countering since he's too busy getting out of the way, blocking, etc.
The con to blitzing is that it tends to be quite linear, and while blitzing, the attacker generally can't defend himself from a well-timed counter. The best strategy against blitzers is to get off the line of the attack and counter as they're coming in.
Both strategies (blitzing and countering the blitz) can be very effective, and it often comes down to the relative experience and intensity of the competitors.
I hear the term alot. The above posts are basicly right. In Wing Chun blitzing is when your only response to an attack is chain punch. Your opponent tries poi jong, you start to chain punch, and do nothing else until you two break contact.
Pros - 'if your opponent can block 50 strikes, throw 51. The last one will get in' - O'Sensei Ngo Dong
Cons - 'Blitzing is a good counter to what your opponent does. Unless you step to the side and do this. Or this. Or step forward into there energy and do this.' - Sensei Wes Shockley.