"Comment2": "This is the next comment"

or

"Comments": ["Here is one", "Here is another!"]

or

"Comments": { "Name": "This is the name of the customer", "Age": "This is the age (0 to 1000) of the customer" }

or

"Values": [ {"Name":"Age", "Value":"20", "Comment":"This is the age of the customer"}, {"Name":"Name", "Value":"Mr. Foo Bar", "Comment":"This is the name of the customer"} ]

The only limit is your imagination.