Most popular or most easy (easiest)? Try to comprehend the comparison the author is making. WoW is very easy, gives rewards for winning or losing, and guides you through the game like a boy scout walking an old lady across a street. EVE, on the other hand, takes everything from you: You die, you lose your ship (unless you have insurance, which is expensive and doesn't fully cover everything 100%), you lose your ships cargo, you lose everything.

And, in 0.0 space, everyone is an enemy and it's a hostile madhouse. Even in secure space, there's still people in small ships that are practically worthless to them that like to grief by attacking docking ships just to get them to retaliate enough to get security ships to blow their high price cargo carriers to rubble. The game is the most hardcore MMO released to date, but also the most fun if you play it just right.