An old Eve-player and friend of mine pursuaded me to join the game half a year ago. After I got started, it was my main occupation during summer, but due to a busy semester I haven't added game time, so currently my account is inactive.
Anyhow, what I like about it is the vastness of the fictional world and the complexity. You need to puzzle and think. In particular I liked exploration/probing. So far I haven't peeked around in the (fan-based) fiction, though, but perhaps that has to do with the fact I read SF and phantasy in the past, while I now think most of it is shallow and one-dimensional (yes, I am critical).
In real-life I'm into humanities a lot (history, semiotics, philosophy, philology, linguistics, you name it). Ten years ago, for instance, I started building my own language and to write fiction, but I after a while I said to myself it was junk, so I quit. Now, since I have some spare time now and then, and because I like to puzzle, I thought to myself: why not joining a forum like this and use the already provided fictional world to start my 'old project' again? So... we'll see.