Cocoa content, or more specifically cacao content, is the amount of cacao in a particular chocolate. In general, the higher the cacao content, the more intense the flavor of the chocolate and the lower the amount of sugar present in the chocolate. However, this isn't always the case. While chocolate with a cocoa content of 70% or more is definitely lower in sugar than those below 70%, the flavor is ultimately determined by the variety of beans that are used and the process by which the chocolate is manufactured.

According to the FDA, chocolate labeled bittersweet and semisweet must contain a minimum of 35% cocoa. Sweet chocolate must have 15%, and milk chocolate only 10%. Those percentages are decidedly low when compared to high-quality semisweet and bittersweet products, which contain anywhere from 55 to 85% chocolate. 

When looking for fine chocolate, look for cacao content.  If you do not see it on the label, you can be sure that not only is the cacao content low, but that there are other undesirable ingredients.