"EVE Online is renowned for it's depth. Its backstory, gameplay and social aspects are all qualities that draw players in. What does immersion in EVE Online mean to you?"
Having spent so much time in TEST and Goon fleets, my idea of immersion with EVE is certainly warped. I fully expect constant crazy links, bad trolls, and frontal assaults on local as part of any PVP activity.
I am one of the many multi account players who had to turn off Incarna to preserve performance, so my immersion is not related to identifying with a space Barbie or finding just the right pair of $75 virtual shoes.
For me, the reason I still play EVE is twofold. Mainly, it is because I enjoy online hanging out with my corp. Specifically, I enjoy the flow experience of PVP, from small gang to epic fleets. When I am in the middle of a confrontation, my focus sharpens and I am in the zone monitoring the FC, yellow boxes, distance, tracking, asking for reps, and all the other battle minutia. This mass PVP experience is so far not available in other games. (Planetside 2 might really bring it.) I greatly enjoy this intoxicating experience until I get distracted and my ship is exploded because of some silly mistake, or occasionally just bad luck. Lag, of course, explains the vast majority of my losses. When Time Dilation hits, I will hopefully develop a new excuse!
The side effect of playing multiple accounts is that you lose the identification with the individual characters. The pilots exist only as vehicles to deliver an experience. That experience is shooting at other ships. The rest of the game is (fairly lame) filler that I have to slog through to keep ships fit and occasionally try to force myself to make some ISK so I can afford to fly and lose expensive ships. I definitely never find PVE immersive, though I hear that incursions are a bit better in this regard.
I think for others like myself that play for PVP, CCP really hurt our feelings by dishing out Tyrannis and Incarna, while severely nerfing our ability to quickly farm up ISK in anomalies. At this point I do not believe in CCP anymore, but they have me hanging around while I wait for something better to come along. My sincere hope is that CCP can re-capture the vision before they destroy the game I have enjoyed for years.