Everyone who has a lot more experience with this than I do has already given really good feedback, so I'll just add my opinion.
If it is always long distance and never face to face and has no history of face to face meetings, I really don't believe that can work.
I believe that people MUST meet face to face eventually on a regular basis and often if the relationship is to mature to something permanent.
I don't believe in crushes over the Internet. My snotty opinion is that it is immature and reaks of high school crushes.
One can meet over the Internet and get to know each other through that and phone, but the true lie detector is seeing the person in person and seeing their stories match up as truth every time.
I could never EVER blindly move in with someone after only Internet or phone conversations.