Meh, I've been living with my boyfriend for six years (met 7.5 years ago on a different MMO). IT CAN BE SAFE AND GOOD.

But, here's my advice: do not date someone long distance UNLESS you have a backup plan, and don't waste so much time with someone you haven't met in person. That way, you can figure out real quick if you are the only one or if they have a little something on the side -- or if you're the little something on the side.

General safety tips when meeting Internet people:

Always, even if the person seems like a great person, BRING SOMEONE WITH YOU when you visit or they visit you.
Don't give them your address until you're comfortable and you have met.
Also, whenever meeting anyone from the Internet... meet at a public place, like an indoor mall or restaurant. Do not let them know where you parked.

Of course, these rules are a bit more lax if you have a mutual RL friend in common that introduced the two of you. But better safe than sorry.