Since EVE Online launched back in 2003 it has been a subscription-based MMO. With the introduction of alpha clones, it is finally making the jump to free-to-play.
In November, developer CCP will release something it is calling alpha clones. In the fiction of EVE every player is a clone, which explains why players can respawn after their ship is destroyed. The alpha clones are, in EVE lore, a cheaper model of clone. It learns more slowly than a traditional clone; it can't develop its skills to the same level of traditional clones, but it can do everything else a traditional clone can do. It can fly ships, trade, mine, take part in combat, or just sit in station chat and insult players.
Here's EVE's executive producer to explain it more fully:
If a player ever decides to subscribe, their alpha clone can be upgraded to an omega clone (which is the lore term for a standard subscription account). And, if a player's subscription lapses then they are still able to play the game, though they must play as an alpha clone. Their skills aren't lost but they are not able to access them. So, if you've a ship that an alpha clone doesn't have the skills to fly then you will not be able to fly it until you have resubscribed.
You can read more about it in CCP's blog post.
Over the years EVE has tried to adapt to the changing fashion. Back in 2008 CCP introduced an ingenious system it called PLEX that let players spend in-game money to buy subscription time from other players willing to sell it. This meant that players who liked EVE but had little time to play could buy plex for real money and sell it in-game for in-game money from players who had the time to play but not the money to subscribe. As well as letting players pay for the game with the resource they had available (cash or time) it pretty much wiped out gold farming, which had been a real problem for EVE.
EVE is still a huge game and it's started moving into really interesting areas, with players now able to build massive space citadels anywhere they want in the game, but I wonder if CCP is seeing the game's player numbers diminish or at least slow, which may have been what's pushed them to make this change.