EVE Online is an open-ended Massively Multiplayer Online Game (MMOG). Most other MMORPGs focus
on a structured playing style with predictable outcomes and monotonous leveling.
This seemingly innocent fact is why EVE is so different from almost all other MMORPGs,
as the players have an incredible impact on how the game develops.
A unique aspect of EVE is that it is run on one server.
In EVE you can find over 10,000 players at any given time interacting in the same persistent universe.
Other MMORPGS are played on multiple servers called Shards; these have a limited number of players on each,
usually between 500 and 3000.
The bottom line is that EVE is a rich and immersive universe centered on human interaction.
Players can play the game as a simple space trader or endeavor to control the largest, most powerful company in the universe.

Above is extracted from EVE Online MMORPG players guide, personally I can add that I’m playing EVE Online
over 2 years already... and not planning to quit any time soon.
It IS complicated, but only as much as you want it to be.
And you can always switch tactics, profession, specialization, anything you like to switch if you are bored.
See you in EVE.

---