Goblins are the fastest moving troop in Clash of Clans and deals double damage against various enemy buildings and structures such as Town halls & Clan Castles. The main purpose of goblins is to gather resources, they can gather resources very fast from a raid, and a whole strategy is formulated around their technique of gathering fast resources, called Milking.
The offensive strategy involving goblins are best suitable for stealing various types of resources. Giants or wall breakers can be used to cave a path to enemy storages or mines and collectors. The enemy defense structures such as wizard towers or troops such as mortars can be led confused by deploying a high health troop like giants. Now when all enemy buildings and army are busy fighting, goblins can be used to steal resources.
This specific class of troop can be used as a offensive army too. The quickest movement among all troops makes them very useful to get rid of very small number of giants. Their attack and movement speed is highest among all classes, rendering them useful in specific situations. They can be upgraded from level 1 to level 7, highest level has extra parks and looks bright orange in color.
The drawbacks of goblins are that they have low health points, and very vulnerable to various type of melee or piercing attacks. Even their resource building strategy makes them vulnerable, as they ignore all enemy troops or defensive buildings while collecting resources, making them a soft target for enemy.