Many hardcore gamers have had difficulties in classifying Second Life, as it is not really a game. It’s an MMO of course, but without any gameplay! This is, incidentally, why always cringe a bit when someone says they "play" Second Life.
One of the categories that has been devised to classify Second Life and similar worlds, is ‘social world’ which nicely describes Second Life’s main attraction: interaction with other residents.
Eve Online is nothing like that, at least not yet. It’s a real game with gameplay, goals and rules, where pilots make a profit, get shot at and occasionally even get podkilled (not a permanent form of death, luckily).
And yet, Eve Online is not like the average MMORPG either. Eve’s single shard universe and it’s open design allow for interaction between all players online on any given moment, and a freedom of (career) choices and things to do that is really unique. There is almost no grind and, apart from some specific missions, there are very few linear paths you must follow. You get to do what you'd like to do within your possiblities, it's really up to you! In this regard, Eve Online shares the openness of social worlds like Second Life.
And I think will get even more social in the foreseeable future. For years now, there has been talk about "ambulation" or “walking in stations”, which is the ability in Eve Online to dock your spaceship at a station, leave your spaceship, walk to a bar or your captains' quarters and interact there with other avatars like the one depicted here. This is quite a big development, given that there has never been a true avatar in Eve Online! I have never seen more than my avatars' mugshot, which is on the login page, but this is set to change with “walking in stations”.
In development for years and repeatedly demonstrated, this development could potentially alter the way Eve Online is inhabited by it’s pilots, as it is truly a social innovation in the game, liberating the avatar from the spacecraft and allowing for more social interaction than already possible now. Certain parts of Eve Online – for instance the bars to be opened at the promenades of high security space stations – may soon resemble Second Life more than some of Eve’s hardcore pirates may find appealing. I wonder if that will lead to new usages of Eve Online? Will there be business meetings at a space bar, somewhere in Eve's near future? It's certainly possible, even though the current subscription structure prevents irregular casual use and makes such scenarios unlikely.
We don't know when "walking in stations" will hit Eve Online. I'm hoping for the first post Apocrypha expansion, which is set for late 2009, but CCP hasn't made any official announcements yet.