From my point of view, and I have lived in Sweden my entire life, I've always felt that Liverpool is different, it's special. None of my mates have the same connection to their club. They say they care so much and love them and hate their rivals and blah blah, but you just don't see any passion in them.
Liverpool do special things, I can make up a long list of things that makes this club special, to name a few;the tribute to Liam back in 08 (I believe it was), the way we always back our manager (Sorry Roy), how we sing YAWN even after a heartbreaking loss (ataturk at halftime), Carra's testomonial game, the internet-terrorists, the way we care about our traditions and history (Bill shankly and hillsborough for example) and let's not forget RAWK.
But the case for me is simply I don't believe they care as much as I do about their club. For example, a friend of mine is a barcafan and during the second leg in the 1st roundagainst Arsenal he wasn't hoping for Barca to win. Well he did, he just wanted them to win after penalties because that would make it more exciting. What the feck is that about?
Maybe it's easier for 'outside of England' fans to feel connected to Liverpool than to any other club, because it's different. It's special.