A few administrative details: first of all, my personal examples will be drawn almost entirely from World of Warcraft, because that is the only MMORPG (that's "muh-mor-pug-guh," for those of you not already acquainted with Zero Punctuation) I have played for an extended period of time.  I may have stories and links about others (FFXI, which I played briefly, and EVE, which makes even the "real" news with relative frequency), but WoW is my area of relative expertise.

Perhaps it would be best to start with the range of perceptions of WoW and other MMORPGs.  As I said, range.  From the perspective of people who play these games, there can be associated feelings of pride ("It's so cool!"), prickly-ish pride ('Yeah, I play it.  So what?"), shame ("Well, I wasn't going to admit it..."), and group condemnation ("Yep ... most of these people are assholes").  From the perspective of people who do not play, I would argue that there are four main groups: those who disdain the games and find them humorous ("Have you SEEN those people?"), those who are indifferent ("I've never heard of those games"), those who are just really confused ("I've heard a lot about them, but I don't know what's going on"), and those who see videogames as a great social evil ("They're murdering our kids!").

Where do I stand on this?  (Yes, good idea, let's get my prejudices out in the open.)  I think they're pretty fun, with varying levels of good implementation, and very different player bases.  The implementation was the reason I quit FFXI for WoW, and the player base and gameplay both are reasons that I failed to stay involved in EVE Online (despite my major in Economics).  WoW allows me the ability to interact with others or not as I choose, which is deeply important, because of John Gabriel's Greater Internet Fuckwad Theory.

I should also tell you my theory about society and MMORPGs.  My personal belief is this: the general disdain of MMORPGs and of those who play them spurs the ardent detractors of videogames to use dubious logic, statistical evidence, and anecdotes in order to portray videogame-related violence and suffering as a social evil in itself and not as a symptom of larger social problems, and the the disdain allows these detractors to continue said activities with muted social assent.  Whew.  In other words, were we to make this an outline-type thing:
I. Starting point: general social disdain for
    a. MMORPGs ("Geeks play those"); and
    b. People who play MMORPGs ("Geeks!")
II. Videogame-related violence of two types:
    a. Directly related ("Damned loot ninja!  I KEEL YOU!"); and
    b. Indirectly related ("My son committed suicide and had Everquest installed on his computer.  Clearly, Everquest is to blame")
III. General social ideas about change and technology
    a. "When I was your age, I didn't spend 5 hours per day on the computer!"
    b. "The media is giving our children dangerous ideas about..."
        i. Violence
        ii. Sex
        iii. Acceptable behavior
IV.  People draw somewhat predictable conclusions
    a. "Someone who liked video games did [activity]"
    b. "Perhaps the game is to blame!"
    c. "Oh my god, everyone's going to go nuts!"
    d. "Won't someone please think of the children?"
V. People collect statistics
    a. Non-representative samples
    b. Biased statistical methodology
    c. "Look, an anecdote!"
VI. No one calls them on it
    a. "Well, they have numbers..."
    b. "...and you know those people who play videogames"
    c. "...and our pastor never did like those computer games, either."

Before we go on, what DOES make for good statistics?  As a society we have two main ideas about statistics: they're generally easy to fake, but we trust numbers instinctively.  Also, statistics are boring.  (Three main ideas.)  The first idea is important.  Statistics are easy to manipulate.  They are!  Also, it's very easy to draw the wrong conclusion, because it's easy to twist things so that they SOUND like there's a causal link (which we can NOT prove with statistics), and even if you have the best intentions, it's easy to miss the real relationship, because you're asking the wrong question.
 
Generally, if one sees a correlation:
    a. There might actually be a correlation
    b. We might be picking up white noise in the data (nonrepresentative sample, etc)
    c. Both factors are caused by a third factor that we haven't thought to ask about yet.
Also, anecdotes do not count as valid evidence.  They can illustrate good evidence.  They can encapsulate the issue and lend a less quantitative view.  But on their own, anecdotes are not evidence.  It is one story.  With WoW, we are dealing with 11 million subscribers.  Eleven million versus one.  Yes, I am using an extreme example on purpose.

So ... back to the main issue: namely, are videogames the cause of depression, suffering, ill health, and violence?  On the "it could definitely be" side, our main arguments are that we see directly-related violence, that people are spending indubitably unhealthy amounts of time on the computer before becoming depressed and committing suicide, and that videogames are relatively new, so it is difficult to know what the long-term effects would be.  On the, "it's probably not," side, our main arguments are that unhealthy and obsessive behaviors have occurred over all sorts of non-videogame things, violence has occurred over all manner of stupid things in "real life" too, and videogames are relatively new, so it is difficult to know what the long-term effects would be.
I am going to try to present this as fairly as possible... 

On the more alarming and persuasive side, we have directly-related violence.  In one case, there was a knife fight in an internet cafe about an in-game object that multiple people wanted.  (There's some quasi-dubious links about this here, I couldn't find the actual story.  If anyone has it, I would appreciate the link!)  However, it is difficult to know what this suggests, exactly.  The game is so dangerously compelling that people are willing to risk their life over some pixels?  Why would these pixels matter so much?  The pixels represent objects that will help the player in a quantitative way: level faster (conserving time, verifiably a real-world issue), gain reputation amongst other players, be uber.  It is impossible to determine, to be frank, whether this is the fault of the players for getting so invested, or if it is the fault of the game for preying on obvious motivations.

On the far, far less persuasive side is the depression and suicide issue.  Not to say that this is less compelling - the reason it is such an issue is that depression and suicide are compelling.  But I think if we look at the evidence, we will find that the link between these is not as clear as we might think.  From what does this depression result?  Less social contacts?  Failed relationships online?  Lack of success in the games?  I am going to toss the failed relationships right out.  Yes, it is easy to deceive when you are "hiding" behind an avatar, and anonymity gives a sense of no conequences.  But people jilt each other in love literally every day.  This is a relatively popular activity (you know... in a way). 

On to the "less social contacts."  The general idea is that you spend so much time in the game that you lose your "real" relationships.  This is partially correct, and partially bogus.  I'd say a ratio of one part to two.  The correct part is that when you spend more time in one place, you spend less in another.  More time online is less time offline.  This is true, we can't deny it.  On the other hand, our real-world interactions are not necessarily "meaningful."  We are also assuming that the people who are spending time online WOULD be spending offline time interacting with people face to face. 

Continuing on this track ... the relationships we create online are not, "fake."  Because someone is interacting through an avatar does not mean you cannot get to know them.  Are your conversations necessarily less meaningful because you do not know someone's given first name?  Possibly.  Not definitely.  I know a lot of the people I play WoW with in real life, and I have gotten quite attached to some of the others.

Lack of success is hard for me to talk about.  It has to do with expectations.  If you want to be the absolute best at anything, in MMORPGs or in other aspects of life, a lot of pieces have to fall into place.  For instance, I would really like to be a good sprinter.  But no matter how much I train, I will never be fast.  It just won't happen.  So the question is, are MMORPGs constructed so that people are kept playing through carrot-on-a-stick methods, with little chance of success?  I would argue no to the whole of that - there are so many ways to be successful in WoW that are NOT time-consuming that we can't blame the game in its entirety. 

So ... on to some of the other common accusations:

a) Video games are designed to be "addictive."  Probably not true.  Are they designed to be fun?  Yes.  Are they designed to keep you playing?  Yes.  Are they designed to create physical and mental withdrawal?  ...really not so much.  This is a bit along the lines of the McDonald's problem ("if people didn't keep eating our extraordinarily unhealthy food, they wouldn't be so unhealthy, now would they?"), although I would said that WoW in particular has created the game to be playable by casuals. 

b) Corporations are just in it for the profit.  Yes!  This is true!  But it's also not as bad as you think.  On the down side, the corporations are just in it for the profit.  They don't care overly much about the downsides if the upsides outweigh the bad.  On the up side, though, they're just in it for the profit.  "Wait, wait," I hear you cry.  "That doesn't even make sense!"  But it does.  These corporations are not going to survive if people destroy themselves playing the game on a regular basis.  They are also not (and this is important) trying to do this in order to be evil.  This isn't personal, and it isn't cruel.  You wouldn't accuse your accountant of "just being in it for the profit."  That would be ridiculous.  Of course he is!  And these people make games.  It's what they do.  Of course they're in it for the profit.

c) Videogames are eroding the fabric of our society.  And our morals.  And our teeth.  Okay, not that last one.  Honestly, I don't really buy this one.  Most videogames are rampantly escapist.  However much I might love my mace-wielding, blue-skinned, shaman, I am simply not motivated to go find a mace and start farming pocket change from the local populace.  I am not going to become more violent because I see people behaving in a violent way, or at the very least, this is not a problem that is inherent to videogames, it is a problem that is inherent to people.  This goes back to, "and if your friends jumped off a bridge..."  Your mother has been nagging you about this since kindergarten.  You are responsible for your own actions, and if you actually cannot tell right from wrong and realize that maybe shooting people is a bad plan, there is another problem.  Is it possible that videogames could warp people into violent behavior?  Yes.  Do I buy it as a theme for which videogames should be blamed?  No.

Okay, this is getting very very long.  I could go into actual statistical methods.  I will, if people want.  But not right now.  So, in conclusion: is there a logical basis for suspecting that MMORPGs are the cause of great social ills?  Sort of.  If we think about it logically, the case is far from clear.  Are MMORPGs designed to keep people playing?  Why, yes, they are.  Sopressa!  (If they were not, why would there be so much content?)  Is this a devious and dastardly plot wherein execs prey on us all?  ...no, not really.

These are just my thoughts.  Feel free to disagree.  I just ask that you stay polite.  If you type in CAPSLOCK OF DOOM, I will probably lock the thread.  If you flame me and call me names (or do the same to others), I will probably lock the thread.  Fair warning.