The magic being referred to is that EQ, being one of the 1st true first person MMORPG in 1999, had a lot of danger, exploration, no hand holding, harsh death penalty, community building based on forced grouping/spell mechanics, an economy built on some class abilities (Druid/Wizard Group gates to ease travel, requiring another casting class to bind you to a different location after you died (You had to be grouped with a caster to do this) combined with a very long leveling curve so you would tend to stay in areas for weeks at a time, getting to know other people playing as you would tend to group with a lot of the same people.
That magic varies between EQ / Insert first MMORPG played. For some it was DAOC, for some it was SWG, for others it was WoW. The MMORPG people usually remember the longest and have most fondest memories of is the first MMORPG they played.
With that said, you had to be a certain level to succeed in a zone, but travelling the world and going through all of it to get to your destination was part of the fun. Like running from Freeport to Qeynos because you had a buddy over there. Seeing the bridge at North Karana for the first time and learning it was a safe area. Having to use the sewers in Freeport because you were a Dark Elf and would be insta-killed on site because the guards hated you. The reputation system, although primitive, allowed you to change that if you wanted too by killing your own guards in Neriak. Which a lot did because Sergeant Slate would eat you alive in East Commons. Being able to see at night (Humans were blind as a bat), Infravision gave a red hue around everything which helped you see, and Ultravision for some races gave you the ability to see everything. But honestly if you were human in vanilla, you couldn't see jack shit. The entire world has never been copied to that point in the history of the genre. The questing system was not used for leveling, and a lot of the times you had no idea who had a quest anyway. Or, something as simple as Invisbility to Undead being cast on you and you would hope it wouldn't break as you are trying to get to your group in the basement of unrest - that sort of shit added to the fear/excitement. You knew bad players, unreputable players, and good players. I could go on and on here but I think you should get the point now. And Day/Night cycles were common and weather was already added in - something you hardly ever see anymore. Which gives some games another fakeness to them.