Actually, it's a server team's time. Server persons sleep, go on vacation, and so on.
As the tools get better, that "amount to fill" keeps getting larger and larger.
And, what are the odds that your team is as good as Amazon's?
That said, your team cares about your stuff more than Amazon's team does.
S3 was down unscheduled more in 2008 than we were. (I only know about their major published widely outages, and know about all of ours that lasted more than 15 seconds.)
I realize that's not a perfect indicator, maybe it was an especially bad year for S3/good year for us, nor is their app apples-to-apples against ours, but one of the primary reasons we CAN'T afford to go even to S3 for "cheap" file storage is that it represents a serial reliability problem: both "them" and "us" have to be up for us to make money.
When we price it out, the 3-year fully burdened cost of our in-house storage vs S3 pricing is about a wash. (It's 5-10% in favor of in-house, but I'm sure we're not perfectly fairly accounting for all the tiny costs [someone has to file purchase orders, do shipping/receiving, calculate depreciation and file tickets to let EMC techs into our DCs to replace failed drives, etc, etc] in our model, but that is after accounting for the IT team dedicated to storage and the on-call rotation portion allocated to storage.)
If we were a lot smaller, it would be a no-brainer to try to use cloud services where it made sense, but as Tom said and anamax clarified, once you're at scale and have access to good IT staff in-house, the cloud offerings are not particularly compelling cost-savings measures.
(Edit: I should perhaps clarify. We do use S3 now, in production, for one of our offerings that is not core to our business, and one for which an arbitrary 8 hours of downtime would not present a problem. We also built two years ago the ability to overflow our bulk/cold image uploads to S3 if we run out of space on our in-house storage. Here again, if we suddenly find ourselves having substantial unforecast demand, it's better to go out to a third party than to turn customers away because the disk is full.
99.90% is >>> 0.00%. :) )
Most privacy policies would be hard to live up to anyway storing critical data in the 'cloud', so a large portion of business-it will always be hosted locally or on hardware controlled by the corporation whose responsibility it is to safeguard the data.
(For the record, contrary to this article's title the bottleneck for me has been management all the way)
Cloud Computing is not easy: The person below who claims you can get a cloud application up in a week has clearly never tried to put a mission critical cloud application up at all. Managing virtual servers can be as hard if not harder than actual servers in many cases because you have to automatically track a bunch of items that would normally be static (is the server active, does it have an ip, if so what is that ip, if not you need to assign an ip and then automatically track that ip, etc...)
The Cloud is not necessarily standardized: The above example looks at environments such as Amazon which are hard to maintain because of all the virtual up and down happening. The other end of the spectrum would be services like Microsoft Azure. Azure is easy to use but it's a platform that has to be written to. You write an application in Azure and you have to rewrite significant parts of it to take it somewhere else.
The Cloud is not always cost efficient: The Cloud is only cost efficient up to the point where you can afford to fill a server person's time. Once that happens having a full time server person becomes more cost effective.
Management IS NOT going to be the one pushing this: The article claims IT should adopt Cloud Computing or Management will. Unlikely. In my experience Cloud computing makes people very, very, very nervous. Let's put all our data on someone else's server does not go over well on its own. Add that to the fact that management types have been trained by the world to think "outsourcing = more expensive" (which is true in non-tech areas) and you have a very steep uphill battle.
Sorry for the long comment but a lot of this Cloud hype is getting out of hand. I'm in favor of Cloud computing but we have to remember it's a tool to solve some specific problems. NOT a tool to solve every problem.