I'm reminded by the Stirrup Queens pair of posts about an internet sympathy scam that I was the subject of a few years ago. It turned out that the scammer had perpretrated a previous scam on the same group of people, an extremely friendly, non-IF bulletin board. It's very much a community and includes some dear friends; it's where I met Mr. Spouse.
Although the scammer was not primarily IF-related, it is clear they sought, and obtained, sympathy for similar reasons to IF-related internet scammers. This person had several sock puppets on the message board and those personalities "suffered" from brain tumours, long-term illnesses, and finally two of them "died", one in a motorway pile-up. Along the way one of the characters caught my attention as they claimed to be going through the adoption process. Together with another friend (who, yes, I have met in real life) who has two young children with special needs (I think this was after the first was born but it was definitely before the second was born), and who lived near where this person claimed to live, I got very very caught up in this person's tale, including exchanging emails and promising to chat on the phone (but never quite going through with it, not surprisingly). This deception was very lengthy and complex and drew people in much, much more than the single claim made by someone scamming the blogger Niobe - it was on the scale of some blog scams, though probably more short-lived
This person was caught out by repeated use of the same IP address, or something similar, I believe; this is easier to spot on bulletin boards I think, where the owners have some degree of control. I know that other scammers have eventually confessed or been found out in some way; but although ultimately I do retain my faith in human nature, I guess I find myself thinking "but what if?" when I'm drawn into some stories. As I usually only think this after becoming emotionally invested, I then beat myself up for again becoming potentially emotionally scammed.