Is considered fat. 
It is good for you in many ways: slowing/preventing periodontal disease, anti-inflammatory, anti-oxidant, cardio protective, neuroprotective. And of course tastes so good.

Main stream advice is eat in moderation.

My advice (look for data to back it up  - you shouldn't just trust Internet advice) is eat daily:99-100% chocolate. I eat at least half a bar everyday (99%).