Alt Accounts & Secret Lives...and Risks

One story, certainly not indicative of all or even many, just one that stood out in my mind as a unique and unpleasant experience....

In another world and on another forum a man became aware of both my account identities. He became obsessed with my duality and asked me, among other things, to log into the forum as my sex alt and tell everyone that he was the best sex I'd ever had. I declined. Not long after that, and for largely unrelated reasons, he posted some forum posts vaguely threatening to out my alt in messages that were designed so that only I would be likely to see what he really meant. I didn't like the control that gave him, so I outted myself. To say he was shocked by my response would be putting it mildly.