This is an excellent thread describing how you can judge for yourself over time if what is being described is reliable or "true".
We've had a few fakers. They last for a while. But they do get found out over time. I think of the young girl who represented herself as a full-time nursing student and exiting JW. Can you think of at least three things wrong with that scenario? Being found out is a natural progression, as it is very difficult to compose a three-dimensional person on the fly.
All I have written about my life is true. As far as anyone's perspective can be. My sister and I still argue about details of our shared childhood. We each have our own sets of memories, intertwined. How can you tell? Consistency and time. Nobody could make up the life I have lived. When I develop a friendship on the board, I look for that same consistency.
One of the great highlights since I joined JWD was meeting Blondie and her husband, Irreverent, face-to-face. Naturally, family and friends were concerned. After all, how could I KNOW they were real, if I had only met them over the internet? A girlfriend stood by to dial 9-1-1 if I didn't show up Monday morning. I kept saying, but this is Blondie and Irreverent! I use the same methods of discernment as so many of you outlined here. Consistency over time.
Anyone can be fooled, and it doesn't have to be the internet. Just read Dan0406's story, and weep!
http://www.jehovahs-witness.com/9/104581/1.ashx