Real life is better than online. At least this way one has a more reasonable idea as to if the person is just playing around or is actually serious.
However, online should not be discredited either. TG and I had a fairly lengthy online relationship before it turned to real life. Why? Well for the first 6 months we had the online relationship because we were in the "getting to know you" phase of our relationship. We also got to know each other on a non-BDSM level. And of course there was the fact that were over 2000 miles apart.
I eventually moved to Texas and stayed with him for over a year. Then, after having come back up to Canada to visit family, I was unable to get back and we were seperated nearly a year. It was difficult and it was nearly the end of us on a couple of occasions but we made it. Why? Because we still had online.
Now we live in a community that has absolutely no real life community so we turn to online where we hope we can find others like us to at least communicate with.
TG also had a purely online submissive. I loved her a lot and she never once betrayed TG. We know this because we had known her for years before hand. Now she couldn't be with us physically but the spirit was still there and she remained with us until she died of cancer about 6 months ago. We feel the loss of her just as severely even though we were never given the opportunity to meet her face to face.
She was one of the best friends that I have ever known and I had never seen her in real life. And we all trusted each other. That is the biggest, hardest thing about an online relationship but I would not have traded it for anything else in the world. I am just happy to know that we had that little bit together.