Some research also suggests that the polyphenols in coffee can play a role in decreasing fat accumulation and increasing the metabolism.
Of course, this role of coffee mainly applies to coffee without a lot of calories. So, if you add in all the extras or buy a fancy Starbucks coffee, you might just end up gaining weight instead of losing it.
There are exceptions though. For example, Bulletproof coffee is commonly used as a way to lose weight and this is fairly calorie-laden. You can read more about this idea at the Bulletproof blog.