My opinion on meeting people in real life that you originally met online is that it's functionally no different than meeting someone in the real world - hell, you may get to meet someone you might not have otherwise met in the real world; someone you may have walked by a million times without ever knowing how interesting you'd find them or how well you'd get along. Also, meeting someone online first has the advantage of getting all kinds of information out of the way before you ever bother meeting up in the real world.
I do think that a degree of caution should be taken when meeting a new person from online for the first time in real life, but this is true of meeting strangers in real life as well. Obviously you should let your friends know where you're going (or in the case of the person visiting you, let them know about it), get as much personal, verifiable information as possible, and probably meet in a public place to start with. Similarly, you shouldn't go home with sketchy looking/acting dudes/ladies that you met in a bar, either.
TL;DR - There are differences, of course, but in the end you are still just meeting another human being who resides upon this lovely planet.