I remember a few years ago reading an article written by, possibly, the first person to ever pull a huge investment scam in eve. It involved a high level of detail, including real-life communication, to build up trust with a potential investor, before the scammer pulled the rug and walked away with a couple of bil (which at the time was a massive amount of isk).
Earlier this year we saw the Titans4u investment scheme fall apart when the founder took over 800bil in another long term scam that had taken years to plan and execute.
Scams and heists are of course an integral part of eve, but which others are the really BIG ones?