Can agave nectar be substituted for honey in baking?
You can use agave nectar instead of honey or sugar if you modify your recipe a bit by lowering the amount of liquids.   Agave nectar has more water than honey and is sweeter than honey (about 50% sweeter). 

Honey
Fructose: 41%,
Glucose: 36%,
Water: 18%

Agave nectar
Fructose: 53%,
Glucose: 15%,
Water: 25%

As a starting point in modifying the recipe, keep the amount of water fixed by using less agave nectar than honey (amount of agave = 0.72 amount of honey).  Also, dishes made with agave nectar will brown faster than those made with honey because of the agave's higher fructose content.  Start checking a little earlier.