I think Eve did two things to embrace their online economy - hired a real-life economist to oversee changes and study it, and brought buying and selling of timecards with in-game currency into the game directly. Previously, you could buy timecards outside of the game and offer them to people, but you had to use external means to do so - forums, IM, email etc, with no guarantee of security. CCP went and made an in-game item for the timecards that you can buy and sell directly. By embracing that process they made things more secure for the players, and knocked down an barrier to their in-game economy.

I think you have a point about Eve seeming much more 'grown-up' - the sociology of the game was extremely interesting to me when I played. How alliances formed, mustering up hundreds to thousands of players at the same time for attack and defense, grand strategy, economic effects on alliances and wars, etc. I was in Goonfleet at the time and a lot of what was happening in game and in corp for command and control was evolving into something resembling how the real-life military does things - I was in the USAF at the time and could see the similarities. Stuff like chat rooms for operations, how fleet command was handled, position updates, alerting procedures (Goonfleet had a Jabber server that was used to send out messages telling people to log on for battles).