According to the Azure homepage, it says:
[Storage, measured in GB] (http://www.windowsazure.com/en-us/pricing/details/)
Storage is billed in units of the average daily amount of data stored (in GB) over a monthly period. For example, if you consistently utilized 10 GB of storage for the first half of the month and none for the second half of the month, you would be billed for your average usage of 5 GB of storage.
I don't understand clearly about the term, "utilization" here. Let's say I have 10GB data in my Azure table storage, and only 1 GB (out of 10GB) data is actually "read" during this month. In this case, will I be paying based on the storage space I've been using (i.e., 10GB) or based on the data I have actually read (i.e., 1GB) ?
Azure Storage uses three "knobs" to measure your costs: transactions, out-bound bandwidth, and storage.
In your example, this would be 10gb of data stored, 1 gb of out-bound bandwidth (assuming the consumers are outside of the Azure Datacenter that hosts your application), and any transactions (the REST request/responses used to retrieve information from Storage) you need to get at the data.
However, the average daily stored per period only refers to storage (aka data at rest). Its simply measured daily and an average for the billing period calculated. And if I recall what I've been told it the past correctly, the "daily" amount is the peak you had on any given day. But please don't hold me to that part.
I would suggest reading the following Azure Storage Team blog to understand Billing thoroughly:
http://blogs.msdn.com/b/windowsazurestorage/archive/2010/07/09/understanding-windows-azure-storage-billing-bandwidth-transactions-and-capacity.aspx
