That means you'll draw a card, or more accurately, attempt to draw a card from your empty library and therefore (usually) lose the game.
Win-more cards are deckbuilding traps, in my opinion
The above diagram shows a card, to the left, that is extremely expensive vs a card, to the right, that is very cheap in played condition
5D's WORLD CHAMPIONSHIP 2010 Reverse of Arcadia Bundles ABSOLUTE POWERFORCE ABSOLUTE POWERFORCE Sneak Peek Yu-Gi-Oh
You've got to love the way he fans them out on the table after game one, physically constructing the silhouette of the monster that the Yu-Gi-Oh anime alone has seared into the minds of millions
Zamazenta V Ability - Dauntless Shield Prevent all damage done to this Pokemon by attacks from your opponent's Pokemon VMAX