The obvious answer for a user, after the Megaupload seizure-shutdown, is if you use cloud storage and/or a file locker service with special irreplaceable data - the high-school football tapes when you scored all those touchdowns or led the cheerleader corps, then store it with multiple services. One getting shut down will not cause damages, if you do that. Also, there is local workstation backup in case of a hardware failure or a theft. For backup the ideal is off-site, not the portable drive on the USB port that you keep attached to the computer since a thief is not going to be courteous and leave it behind in taking all else. That is cause to use the cloud. To use file locker services. The problem, file locker folks such as Megaupload appear to have part of the business plan being support of piracy. Or winking at it, at best, and the film-recording people are bloodthirsty over getting their royalties off artists' works. And if you use a file service or cloud account where you only utilize the free five gigabytes of storage and pay nothing, would you only be owed your fee back, i.e., zero in damages, if there is a seizure of a service provider's domain by the feds, as with Megaupload?
It seems simple, the feds shut it down, seizing the files - all of them - as evidence, and then tell private persons who did no wrong - who pirated nothing - to f.o. because the feds owe them nothing - people will further dislike the government that apart from such things as file sharing - cloud storage, has given citizens ample cause for hate, fear and loathing. The attitude of we-owe-nothing because you assumed all risk in dealings with these people, including the risk of government actions, is an attitude that begs further attention.
Your data is your property. Intangible personal property, unlike land and buildings. But property.
If it is seized by the government, are you not owed "due process" under the Fifth Amendment? When the government seizes land and buildings, they traditionally have been constrained to not adopt an f.o. attitude.
So, what's the real difference?
Then there is the responsibility placed by the Constitution on the feds to honor and not impede "freedom of contract." While each case may need exposition on what contract freedoms are fundamental, if you place property in custody of another are you not entitled to reasonable expectations? When local authorities shut down a pawn shop they do not walk off with the goods and tell people still having redemption rights to go away. Again, where's the difference?
All that is a prelude, to this online item giving some detail on the very issue being litigated - innocent data owners who entrusted stuff to Megaupload apart from any piracy that may or may not have happened.
As a side-note, giving Google returns on the Constitutional provisions begs the question of nuances that may apply. However, in conforming existing law to new situations, generality and a fresh look apart from nuances of precedent in other situations is not necessarily a bad thing. Precedent is precedent. Common sense is not necessarily in tune with precedent, especially if precedent is reviewed by judges lacking rudimentary common sense (and such judges do exist). Cloud storage and file lockers are new - the entire web and present levels of connectivity and access to information stores of unprecedented magnitude, is access from the home not ever available before. However for perspective, the law of bailments is older than Blackstone, so what should courts do? Most bailment litigation is between bailor-bailee, the two private parties, and most of it is in situations where government action is absent - vs. Megaupload where government action was the precipitating cause of having to ask about innocent third party rights and expectations the law should honor.
_____________UPDATE____________
Two members of the US House, one Republican and one Democrat, propose an "Internet Bill of Rights," but it seems the old fashioned founding-fathers' Bill of Rights is more on point for the innocent Megaupload user than their proposal; online here.