http://www.wizards.com/Magic/Magazine/Article.aspx?x=mtg/daily/arcana/1067

The Golgari don't discriminate based on paltry factors like whether a creature is alive. Any warm—or cold—body will do the job. That's why the scavenge mechanic is so powerful: when you put that card's power back on the battlefield in the form of +1/+1 counters, it's like the creature never died at all!

The first few turns will play out just as they would with any deck: cast creatures, develop your board, remove threats. Eventually, though, your opponents will be forced to kill your Drudge Beetles, Korozda Monitors, and Terrus Wurm. That's when the scavenge mechanic kicks into gear. Pile a swath of +1/+1 counters onto whichever creature you have left, and your opponents can't help but succumb to the assault.

The key to winning with this deck is to always have a creature on the battlefield. Because so many of your cards can be reused from the graveyard, it will often be the best play to trade resources with your opponent. At the same time, though, you don't want to leave those scavenge cards stuck in your graveyard. If you can scavenge, say, a Dreg Manger, to put three +1/+1 counters on a Daggerdrome Imp, you'll be attacking with a 4/4 creature with flying and lifelink every turn. With numbers like that, who cares what your opponent is up to?

If you want to take the graveyard aspect of this deck even further, look to Jarad, Golgari Lich Lord, who can transform a graveyard full of fresh bodies into a powerful asset. Alternatively, if a fast Wild Beastmaster–fueled assault is more up your alley, the regenerating Lotleth Troll provides a ready docking bay for all the +1/+1 counters you'd ever care to throw around.