The first games I played on a regular basis that were even remotely near "massively multiplayer" were Simutronics Gemstone III and DragonRealms, back when dinosaurs ruled the Earth and having an AOL account got me shunned from the Internet community. I mean, no game has come close to the GS/DR combo in terms of long-term playability for me. I happened to be booking appontments for E3 and chatted with one of the guys from Simu, who happened to be an old DragonRealms GM. After a bit of talking, I was granted access to the games again--filled with fear, of course, because if my mom finds out I'm playing again, I'm so grounded--and returned to the lands of my youth.
Of course, much has changed. Gemstone has gone up a number to Gemstone IV, and it has lots of new races, and a slick new interface where back in my day, we had a line for typing and a big box that displayed output and we liked it, by gum!
I went to DragonRealms (pretty much the same so far, which is good, as I am old and I fear change) and found myself going through the character creation as if it was yesterday. And what I found in a couple hours of play is this: Text-based games are still way more immersive than they have any right to be. They're certainly more immersive than most of the games I've played recently (save Guitar Hero, it does take a lot to get me jumping up and down). Instead of being some guy on a screen, I've got everything picked for my character, from standard race and profession stuff down to his exact birthday and birth year.
I think this is why role-playing has seldom made the jump from text-based games like MUDs to graphical games. Not only can I define the character down to little quirks and mannerisms, how I play the guy matters. If I act like a jerk to people, all they'll remember is that <Embarassing Fantasy Name Here> is a jerk, not that I'm wearing shiny armor and have obviously completed lots of raids. I'm not saying I'm typing "Forsooth, fair lady, doest thou know wherest I might find a weapons shop?", but it's be far easier to get into something like this than moving around characters on a screen. Text-based games still have more narrative strength for me, even though I'm playing it on a computer with enough juice to make a small sun in full 3D with lots of lens flares.