"Their big argument in defence is that they are doing exactly the same as Google; that is, simply linking to files.
"The most fundamental legal question to answer is were they grossly negligent if they continued to offer the service once they knew it was being used to infringe copyright.
"It is a hard question and from a legal and political sense the question is to what standard do you ask a prosecutor to show intent?"
Prosecutor Hakan Roswal
http://news.bbc.co.uk/1/hi/technology/8002938.stm
I'm no expert when it comes to Swedish law, but I can't see the issue with the guilty verdict.
It's quite clear to anyone that they were not hosting any copyrighted material. But that doesn't seem to be what they were found guilty of. It's equally clear that they intended the site to be used for sharing links to copyrighted material and have made this point clear during interviews. If knowingly providing a means to aid copyright infringement is illegal under Swedish law then there's no argument for their innocence that I can see.
That's not to say I agree that a year in prison is the right way to sort this out...