Through rootschat and with the help of Google, a cousin in the US got in touch with me, and the outcome of that was the reuniting of my father with his half-brothers, whom he hadn't seen or heard from in over 40 years.
In the chatroom one night I was lamenting about another branch of the tree, and a chatter mentioned there was someone with that name looking for family at GenesReunited. After reading what she said, I joined up just so I could write to the person. She is the 2nd cousin of my father, who was orphaned at a young age and never had contact with the paternal side of her family, and in fact it seemed to have been actively discouraged. She was 73 when we met up and she had not known a single paternal relative.