Regarding mens rea, I imagine it's tougher to argue that you thought you were legal technically than to argue you had no idea you might be breaking the law? E.g. Someone who has never heard of magic mushrooms but find then growing and sells them has a better chance of not being convicted for selling illegal drugs than someone who knows and had researched the laws and thinks they have a technicality to allow them to sell? Of course that's assuming they were wrong about the technicality.
"Well, of course everybody knows that the internet is being used for legitimate and illegitimate uses. I think every online service provider has the same challenges that we have. YouTube, Google, everybody is in the same boat. So what you need to understand here is that we provided the content owners with an opportunity to remove links that were infringing on their rights. So, not only did they have an online form where they could take down infringing links, they had direct delete access to our servers so they could access our system and remove any link that they would find anywhere on the internet without us being involved. They had full access and we’re talking about 180 partners, including every major movie studio, including Microsoft and all big content producers and they have used that system heavily and you need to understand that that system was not even something that was even required by the law. We provided that voluntarily and they have removed over 15 million links."
From: http://www.3news.co.nz/tvshows/campbelllive/kim-dotcoms-firs...
On the other hand, who can say whether content is illegal in all contexts. Perhaps your pirated movie is my legitimate backup.
If this really is the only issue it seems like quite a weak case to me, as with more diligence the copyright holders could have removed all copies. But I guess we'll never know all the details.
Then consider how much years Google needed to start to be even slightly effective. Wasn't that dragging the feet?
The justice for small guys and superrich is not the same. Kim is a small guy in this comparison.
All Megaupload needed to do was allow copyright holders to play the cat and mouse game of takedowns to be within the law. A DMCA takedown doesn't have the oversight from a judge or anything, it can be totally wrong and there's really no reprocussions (as we've seen on youtube multiple times, this occurs frequently.)
You cannot expect Megaupload to delete the content from their servers, as their business is data retention. You also cannot expect Megaupload to flag files as DMCA'd and not allow them to ever be downloaded, the fact that their entire business model is people sharing content and the sheer amount of DMCA requests they recieve makes it impossible for them to investigate each case properly.
The DMCA protects him by simply allowing takedowns of a single link. The content can stay, and he can stay within the bounds of the law by some external individual creating an additional link to be inevitably DMCA'd again.
What the prosecutor might argue however, is that mens rea is not needed for cases of assisting criminal copyright infringement. This is what happened in the pirate bay trial, as the prosecutor brought up precedent cases in which an friend of an accused held up a window during a burglary, and got sentenced even if he was not aware what his friend was up to.