This happened several years ago in the Queer As Folk fandom. A writer passed himself off as polyamorous, at that time living with another man and raising a baby daughter, courtesy of a friend who donated her eggs and carried the baby for them. He also bravely dealt with the aftereffects of a traumatic head injury he sustained while playing on an ice hockey team. He wrote original M/M fiction and had a pretty big following in the QaF fandom (I don't specifically remember his name, Christian something) and he especially had a very intense internet relationship with one of the women on my flist. Over the years he posted pics of his daughter, but never himself or his partner. When it eventually came out that "he" was a "she" playing an elaborate hoax on the internet, the aforementioned fan was devastated and publicly humiliated. After many posts about how she didn't know and never suspected, she deleted her journal and quietly went away. Turns out that a lot of people knew of the sham, they just kept it to themselves, or played along, because they assumed everyone else knew. I had never friended him, so I watched this play out in journals of other on my flist.

Some people are seriously fucked up and with the internet, it's so easy to lie and take advantage of others. It's one of the reasons why I keep my flist so small. I blab all the time about my personal life, and I like to know who I'm blabbing to :)